Artificial Intelligence glossary

AI glossary

300 terms across 65 topics.

A

Accuracy

The proportion of predictions that are correct under a defined scoring rule.

in: AI evaluation › Choose measures that fit the task

Activation function

A function that transforms intermediate values, often adding nonlinearity.

in: Deep learning › How a neural network learns

Adapter

A small trainable component added to adapt an existing model.

in: Fine-tuning › Choose an adaptation method

Agent Card

In the A2A documentation checked 2026-10-09, metadata describing an agent’s identity, capabilities, skills and interaction requirements.

in: Agent interoperability › Four roles, four integration needs

Agent Client Protocol

Also: ACP

As documented on 2026-10-09, a protocol connecting code editors or IDEs with coding agents.

in: Agent interoperability › Four roles, four integration needs

Agent harness

Software around a model that manages the agent loop, tool routing, approvals, recovery, and run state.

in: AI agents › Agents, workflows, and harnesses

Agent memory

Information retained for reuse across agent steps or sessions.

in: Agent memory and orchestration › Choose what to retain and coordinate

Agent Skills

As specified on 2026-10-09, an open format packaging instructions and resources around a required SKILL.md file.

in: Agent interoperability › Four roles, four integration needs

Agent2Agent protocol

Also: A2A

In the A2A documentation checked 2026-10-09, an open standard for communication and interoperability between independent agent systems.

in: Agent interoperability › Four roles, four integration needs

Agentic workflow

A predefined process that contains model-driven steps or actions.

in: AI agents › Agents, workflows, and harnesses

AGENTS.md

A repository-file convention for instructions intended for coding agents.

in: AI coding agents › Give the agent repository context

AI agent

Also: agent

Software in which an AI model directs some of its own processes and tool use to accomplish a task.

in: AI agents › Agents, workflows, and harnesses

AI ethics

Examining values and responsibilities in AI development and use.

in: AI safety and governance › Name the harms and responsibilities

AI governance

Rules, processes, and accountability for developing and using AI.

in: AI safety and governance › Name the harms and responsibilities

AI literacy

The ability to understand, use, and critically assess AI.

in: AI in education and research › Use AI to support learning

AI model

A computational representation used to make predictions, generate outputs, or choose actions.

in: AI foundations › What AI means

AI safety

Work to identify and reduce harms caused by AI systems.

in: AI safety and governance › Name the harms and responsibilities

AI winter

A period of reduced confidence, funding or activity following unmet AI expectations.

in: History of AI › Milestones and tests

Alignment

Also: AI alignment

Efforts to make AI behavior match intended goals, values and constraints.

in: AI alignment › Goals, constraints and behavior

Anomaly detection

Also: outlier detection

Identifying observations that differ from expected patterns.

in: Predictive machine learning › Match the method to the output

API

Also: application programming interface

A defined software interface through which one component can interact with another component’s capabilities.

in: AI integration standards › Choose the interface and control access

Approximate nearest neighbor

Also: ANN search

A method for efficiently finding vectors likely to be close without checking every candidate.

in: Embeddings and search › Representations and retrieval methods

Artificial general intelligence

Also: AGI

Proposed AI intended to learn, reason, and apply knowledge across a wide range of tasks; there is no universally accepted test for it.

in: AI foundations › What AI means

Artificial intelligence

Also: AI

Computer systems performing tasks associated with perception, reasoning, learning, or action.

in: AI foundations › What AI means

Artificial superintelligence

Also: ASI

Hypothetical AI that surpasses human cognitive capabilities across most domains.

in: AI foundations › What AI means

Attention

Also: attention mechanism

A computation that weights information according to its relevance to another representation.

in: Neural-network architectures › Architecture building blocks

Augmentation

Using technology to assist people in performing their tasks.

in: AI at work › What AI can change in a job

Authentication

Verifying credentials and the identity they assert.

in: AI integration standards › Choose the interface and control access

Authorization

Deciding whether an authenticated party has permission to access a particular resource or service.

in: AI integration standards › Choose the interface and control access

Automatic speech recognition

Also: ASR, speech to text, STT

Converting spoken audio into text.

in: Speech and audio AI › Choose the speech task and measure its output

Automation

Having a system perform tasks with reduced direct human execution.

in: AI at work › What AI can change in a job

B

Backpropagation

A method for calculating parameter gradients through a model’s chain of computations.

in: Deep learning › How a neural network learns

Base model

A pretrained model before a particular instruction or task adaptation.

in: Foundation models › What kind of model is it?

Baseline

A reference approach against which another approach is compared.

in: AI evaluation › Choose measures that fit the task

Batch size

The number of examples processed in a batch for a training iteration.

in: Deep learning › How a neural network learns

Benchmark

A defined collection of tests and a procedure used to compare performance.

in: AI evaluation › Choose measures that fit the task

Benchmark contamination

Prior exposure to evaluation material that can distort measured generalization.

in: AI benchmarks › What makes two scores comparable?

BF16

Also: bfloat16

A 16-bit floating-point format with a wider exponent range than FP16.

in: Model quantization › What fewer bits change

Bit width

The number of bits used to represent a value.

in: Model quantization › What fewer bits change

BM25

A keyword-ranking method that uses term-frequency and document-length normalization.

in: Embeddings and search › Representations and retrieval methods

C

C2PA

Also: Coalition for Content Provenance and Authenticity

An organization that develops technical standards for certifying the source and history of media content.

in: AI media and information › What provenance can tell you

Calibration

How well predicted probabilities match observed outcome frequencies.

in: AI evaluation › Choose measures that fit the task

Carbon footprint

Greenhouse-gas emissions attributed to an activity within stated boundaries.

in: AI environmental impact › What does a footprint include?

Causal inference

Estimating effects of interventions under explicit assumptions and evidence.

in: Causal AI › What makes a claim causal?

Chain of thought

Also: CoT

Generated intermediate reasoning text that need not reveal the model's actual causes.

in: LLM inference and reasoning › Choose how the next token is selected

Chat template

As documented on 2026-10-09, rules that convert conversations into a tokenizable string in the format a model expects.

in: Local AI runtimes › Choose a runtime and application

Chatbot

Software that interacts with people through conversational messages.

in: AI foundations › What AI means

Checkpoint

A saved model or training state that can be loaded later.

in: Large language models › From text to tokens and back

Chunking

Splitting source material into pieces for processing or retrieval.

in: Retrieval-augmented generation › The retrieval and answer pipeline

Citation

A reference to a source intended to support a statement.

in: Retrieval-augmented generation › The retrieval and answer pipeline

Classification

Predicting which category an input belongs to.

in: Predictive machine learning › Match the method to the output

Closed weights

Also: closed-weight model

Model parameters not distributed to users.

in: Model access and licensing › Access, weights, and the OSI definition

Clustering

Grouping items according to similarities in their data.

in: Predictive machine learning › Match the method to the output

Code completion

Suggesting continuations or snippets while code is being written.

in: AI for coding › Use assistance without losing the thread

Computer use

Operating a graphical interface through observations and input actions.

in: Computer-use agents › Interfaces and actions

Computer vision

Also: CV

Computational methods that extract information from images or video.

in: Computer vision › Match the task to the output

Confounder

A factor influencing both a proposed cause and its measured outcome.

in: Causal AI › What makes a claim causal?

Content Credentials

A cryptographically bound record that records an asset’s provenance, such as its origin, modifications, or use of AI.

in: AI media and information › What provenance can tell you

Context compaction

Reducing stored context by summarizing or otherwise compressing it so a workflow can continue.

in: Context engineering › What belongs in context

Context engineering

Designing which instructions, information, and state a model receives across a workflow.

in: Context engineering › What belongs in context

Context window

Also: context length

The maximum context length supported under a stated model and configuration.

in: Large language models › From text to tokens and back

Continuous batching

Scheduling that lets new inference requests join work already being processed, rather than waiting for an entire fixed batch to finish.

in: Model serving › Model serving fundamentals

Convolutional neural network

Also: CNN

A network that uses shared local filters to detect structured patterns.

in: Neural-network architectures › Architecture building blocks

Copyright

In the United States, the Copyright Act of 1976 was adopted on 19 October 1976. Copyright concerns legal rights in original works of authorship fixed in a tangible medium of expression.

in: AI law and regulation › Find the law, status and date

Cosine similarity

A measure comparing the directions of two vectors.

in: Math for AI › Read vectors, matrices, and tensors

Counterfactual

An alternative outcome considered under a different action or condition.

in: Causal AI › What makes a claim causal?

CPU

Also: central processing unit

A general-purpose processor that executes a computer’s instructions.

in: AI hardware › Processors, memory, and accelerator support

CUDA

NVIDIA’s platform and tools for programming compatible GPUs.

in: AI hardware › Processors, memory, and accelerator support

D

Data exfiltration

Unauthorized transfer of information outside its permitted boundary.

in: AI security › Threats in prompts and data

Data leakage

Information unavailable at deployment improperly enters training or evaluation.

in: Data for AI › Build a dataset and keep evaluation honest

Data poisoning

Deliberate manipulation of training or reference data to alter system behavior.

in: AI security › Threats in prompts and data

Data provenance

The recorded origin, permissions, and transformation history of data.

in: Data for AI › Build a dataset and keep evaluation honest

Data science

Using statistics and computation to analyze data and communicate findings.

in: AI foundations › What AI means

Dataset

A collection of examples used for analysis, training, or evaluation.

in: Data for AI › Build a dataset and keep evaluation honest

Decision tree

A model that follows branching conditions to reach a prediction.

in: Predictive machine learning › Match the method to the output

Decode

Also: decoding

The inference stage that generates subsequent output tokens.

in: LLM inference and reasoning › Choose how the next token is selected

Decoder

A model component that produces outputs from internal representations or context.

in: Neural-network architectures › Architecture building blocks

Deep learning

Also: DL

Machine learning that uses neural networks with multiple processing layers.

in: Deep learning › How a neural network learns

Deepfake

Manipulated or synthetic audio or visual media that seems authentic and features a person who appears to say or do something they never said or did, produced using artificial intelligence techniques.

in: AI media and information › What provenance can tell you

Denoising

Removing or reducing noise in a representation.

in: Image and video generation › How generation methods work

Dense model

A model that uses the same main network rather than selecting expert subnetworks.

in: Neural-network architectures › Architecture building blocks

Diffusion model

A generative model learning to reverse a process that adds noise.

in: Image and video generation › How generation methods work

Digital twin

A digital representation of a particular physical system or process.

in: World models and simulation › Simulation, models, and digital twins

Dimensionality reduction

Representing data with fewer dimensions while retaining useful information.

in: Predictive machine learning › Match the method to the output

Distillation

Also: knowledge distillation

Training a student model to imitate signals from a teacher model.

in: Fine-tuning › Choose an adaptation method

DPO

Also: direct preference optimization

A method that optimizes preferred responses over rejected responses without an explicit reinforcement-learning loop.

in: Preference and reward training › Feedback, reward models, and optimization

E

Embedding

Also: embeddings

A learned numerical representation of text, images, or other items.

in: Embeddings and search › Representations and retrieval methods

Embodied AI

AI that perceives and acts within a physical environment.

in: Embodied AI › What makes AI embodied?

Encoder

A model component that converts inputs into internal representations.

in: Neural-network architectures › Architecture building blocks

Entropy

A measure of uncertainty in a probability distribution.

in: Math for AI › Read vectors, matrices, and tensors

Environment

The setting that responds to actions with observations and feedback.

in: Reinforcement learning › The parts of a reward-based problem

Epoch

One traversal of the defined training set, with each example processed once.

in: Deep learning › How a neural network learns

EU AI Act

EU legislation establishing requirements for specified AI systems and models. In the EU, the Act is in force and generally applies from 2 August 2026, with provision-specific dates.

in: AI law and regulation › Find the law, status and date

Evaluation

Also: eval

Measuring behavior or performance against stated tasks and criteria.

in: AI evaluation › Choose measures that fit the task

Expert system

A system that applies encoded specialist knowledge, represented as facts and rules, to draw conclusions in a specific domain.

in: Symbolic and neuro-symbolic AI › Rules and expert systems

Explainability

Also: explainable AI, XAI

Providing understandable accounts of a system’s outputs or operation.

in: AI interpretability › What an explanation does and does not show

Exploration-exploitation

The tradeoff between trying uncertain actions and using currently promising ones.

in: Reinforcement learning › The parts of a reward-based problem

F

F1 score

The harmonic mean of precision and recall.

in: AI evaluation › Choose measures that fit the task

Fair use

In the United States, the Copyright Act of 1976 was adopted on 19 October 1976. Section 107 provides a context-dependent copyright exception evaluated using statutory factors; it is not a universal permission.

in: AI law and regulation › Find the law, status and date

Faithfulness

How well an answer stays supported by its supplied context.

in: Retrieval-augmented generation › The retrieval and answer pipeline

Feature

An input property used by a model.

in: Machine Learning › How models learn from data

Few-shot prompting

Providing task examples inside the prompt.

in: Prompting and context › Instructions, examples, and response shape

Fine-tuning

Also: finetuning

Additional training that adapts an already trained model.

in: Foundation models › What kind of model is it?

Flow matching

Training a model to transform distributions through a learned continuous flow.

in: Image and video generation › How generation methods work

Foundation model

A broadly pretrained model adaptable to multiple downstream tasks.

in: Foundation models › What kind of model is it?

FP16

Also: float16

A 16-bit floating-point numerical format.

in: Model quantization › What fewer bits change

Frontier model

For the Frontier Model Forum’s membership definition, a general-purpose model that outperforms models widely deployed for at least 12 months, based on a range of conventional performance benchmarks or high-risk capability assessments.

in: AI model landscape › Recognize model families

G

General-purpose AI

Also: GPAI

An EU legal category concerning models capable of a broad range of distinct tasks. The EU AI Act, in force and generally applying from 2 August 2026, defines a general-purpose AI model by its significant generality and capacity to perform a wide range of distinct tasks.

in: AI law and regulation › Find the law, status and date

Generalization

A model's ability to perform on new inputs beyond its training examples.

in: Machine Learning › Fit, overfit, and generalize

Generative AI

Also: GenAI

AI that produces new content such as text, images, audio, or code.

in: AI foundations › What AI means

GGUF

As described in the format documentation checked 2026-10-09, a file format for storing models for inference with GGML and executors based on GGML.

in: Local AI runtimes › Choose a runtime and application

GPU

Also: graphics processing unit

A processor suited to many parallel computations.

in: AI hardware › Processors, memory, and accelerator support

Gradient

The direction and rate of a function's change across its inputs.

in: Math for AI › Read vectors, matrices, and tensors

Gradient descent

An iterative method that uses gradients to update parameters in an effort to reduce an objective.

in: Deep learning › How a neural network learns

GraphRAG

A family of RAG approaches using graphs to organize or retrieve information.

in: Knowledge graphs for AI › Represent entities and relationships

Grounding

Connecting an output to supplied evidence or observations.

in: Retrieval-augmented generation › The retrieval and answer pipeline

Guardrail

A mechanism intended to restrict or check system behavior.

in: AI alignment › Goals, constraints and behavior

H

Hallucination

Also: AI hallucination

Generated content presented as factual despite being false or unsupported.

in: Large language models › From text to tokens and back

HELM

Also: Holistic Evaluation of Language Models

Stanford’s framework for evaluating foundation models with transparent, reproducible methods.

in: AI benchmarks › What makes two scores comparable?

Heuristic

A practical estimate or shortcut used to guide search or choice; it does not by itself guarantee the best answer.

in: Symbolic and neuro-symbolic AI › Rules and expert systems

High-risk AI

AI systems falling within specified high-risk categories under the EU AI Act. In the EU, the Act is in force and generally applies from 2 August 2026; the AI Omnibus amendment sets later application dates for specified obligations.

in: AI law and regulation › Find the law, status and date

Human in the loop

Also: HITL

A workflow assigning a person a review or decision step.

in: Tool use and automation › How a model calls a tool

Hybrid search

Retrieval that combines methods such as keyword and vector search.

in: Embeddings and search › Representations and retrieval methods

Hyperparameter

A setting chosen outside the model's learned parameter values.

in: Machine Learning › Fit, overfit, and generalize

I

Imitation learning

Learning behavior from demonstrations.

in: Robot learning › Learning behavior and transferring it

Indirect prompt injection

Prompt injection arriving through retrieved content, files, or tool outputs.

in: AI security › Threats in prompts and data

Inference

Using a trained model to produce an output for an input.

in: Machine Learning › How models learn from data

Inference runtime

Also: inference engine

Software that executes a model's computations.

in: Local AI runtimes › Choose a runtime and application

Inpainting

Generating or editing content within selected image regions.

in: Image and video generation › How generation methods work

Instruction-tuned model

Also: instruct model

A model additionally trained to respond to instructions.

in: Foundation models › What kind of model is it?

INT4

A four-bit integer representation used in some quantized models.

in: Model quantization › What fewer bits change

J

Jailbreak

An attempt to bypass a model's intended behavioral or safety restrictions.

in: AI security › Threats in prompts and data

JSON Schema

A vocabulary describing and validating the structure of JSON data.

in: Prompting and context › Instructions, examples, and response shape

JSON-RPC

A lightweight, transport-agnostic remote procedure call protocol that uses JSON as its data format.

in: AI integration standards › Choose the interface and control access

K

Keyword search

Also: lexical search

Retrieval based on matching textual terms.

in: Embeddings and search › Representations and retrieval methods

Knowledge cutoff

Also: training cutoff

A stated boundary for training-data recency, not a guarantee of complete knowledge.

in: Large language models › From text to tokens and back

Knowledge graph

A structured representation of entities and their relationships.

in: Knowledge graphs for AI › Represent entities and relationships

KV cache

Also: key-value cache

Saved attention calculations reused when generating later tokens.

in: LLM inference and reasoning › Choose how the next token is selected

L

Label

Also: target

A known answer or target associated with a training example.

in: Machine Learning › How models learn from data

Language model

Also: LM

A model that estimates patterns or probabilities in language.

in: Natural language processing › Choose the language task

Large language model

Also: LLM

A model trained at substantial scale to process and generate language.

in: Large language models › From text to tokens and back

Latency

Elapsed time between a request and a specified response event.

in: Model serving › Model serving fundamentals

Latent space

A space of learned representations rather than raw observations.

in: Image and video generation › How generation methods work

Layer

A stage of computation in a neural network.

in: Deep learning › How a neural network learns

Leaderboard

A ranking based on specified tests, preferences, or scoring procedures.

in: AI benchmarks › What makes two scores comparable?

Learning rate

A setting that controls how strongly gradient descent adjusts parameters on each iteration.

in: Deep learning › How a neural network learns

Least privilege

Granting only the access necessary for an operation.

in: Tool use and automation › How a model calls a tool

llama.cpp

As described by the project on 2026-10-09, an inference engine implemented primarily in C and C++.

in: Local AI runtimes › Choose a runtime and application

LLM-as-judge

Using a language model to assess outputs against evaluation criteria. For agent trials, report the judged system's model, tools, scaffold, and environment alongside the result.

in: Evaluating AI systems › Define tests and choose graders

LLMOps

Also: large language model operations

Operational practices specific to language-model applications.

in: AI observability › Operations across the model lifecycle

LM Studio

As documented on 2026-10-09, an application for serving local models through a server interface.

in: Local AI runtimes › Choose a runtime and application

Local inference

Running model computations on a local machine.

in: Local and on-device AI › Where computation runs

LoRA

Also: low-rank adaptation

An adaptation method that learns low-rank updates to selected model weights.

in: Fine-tuning › Choose an adaptation method

Loss function

Also: training objective

A mathematical function that measures prediction loss, which training typically aims to minimize.

in: Deep learning › How a neural network learns

M

Machine learning

Also: ML

Methods that improve task performance by learning patterns from data or experience.

in: Machine Learning › How models learn from data

Matrix

A rectangular grid of numbers used to represent data or transformations.

in: Math for AI › Read vectors, matrices, and tensors

MCP Apps

An extension that lets MCP servers deliver interactive user interfaces to hosts.

in: Model Context Protocol › Connection roles and server capabilities

MCP client

A connector created by a host that communicates with one MCP server.

in: Model Context Protocol › Connection roles and server capabilities

MCP elicitation

A standardized way for a server to request additional information from a user through the client.

in: Model Context Protocol › Connection roles and server capabilities

MCP extension

An optional, opt-in capability that adds functionality beyond the core protocol.

in: Model Context Protocol › Connection roles and server capabilities

MCP host

The AI application that coordinates user interaction and manages MCP client connections.

in: Model Context Protocol › Connection roles and server capabilities

MCP prompt

A server-provided template of structured messages and instructions that a client can retrieve and customize with arguments.

in: Model Context Protocol › Connection roles and server capabilities

MCP resource

Data or content a server exposes to a client under a resource URI.

in: Model Context Protocol › Connection roles and server capabilities

MCP server

A local process or remote service that exposes context and capabilities through MCP.

in: Model Context Protocol › Connection roles and server capabilities

MCP Tasks

An extension that lets a server return a task handle for certain requests so a client can poll for the eventual result.

in: Model Context Protocol › Connection roles and server capabilities

MCP tool

A named, schema-described capability that a server exposes for a client to invoke.

in: Model Context Protocol › Connection roles and server capabilities

Mechanistic interpretability

Investigating internal model mechanisms associated with particular behaviors.

in: AI interpretability › What an explanation does and does not show

Metal

Apple’s interface for graphics and GPU computation.

in: AI hardware › Processors, memory, and accelerator support

Mixture of experts

Also: MoE

An architecture that routes inputs through selected specialized subnetworks.

in: Neural-network architectures › Architecture building blocks

MLOps

Also: machine learning operations

Practices for developing, deploying and maintaining machine-learning systems.

in: AI observability › Operations across the model lifecycle

MLX

As described by the project on 2026-10-09, an array framework for machine learning on Apple silicon.

in: Local AI runtimes › Choose a runtime and application

MMLU

Also: Massive Multitask Language Understanding

A multiple-choice benchmark that measures multitask accuracy across academic and professional subjects.

in: AI benchmarks › What makes two scores comparable?

Modality

A form of information, such as text, an image, or audio.

in: Multimodal AI › What counts as multimodal?

Model bias

Also: algorithmic bias

Systematic tendencies or errors that can disadvantage people or distort results.

in: AI safety and governance › Name the harms and responsibilities

Model card

Documentation describing a model’s intended uses, evaluation, and limitations.

in: AI model landscape › Read capability and documentation claims

Model Context Protocol

Also: MCP

A JSON-RPC protocol for applications to share context with language models and expose tools and capabilities.

in: Model Context Protocol › Connection roles and server capabilities

Model drift

A change in a model's observed behavior or performance over time.

in: AI observability › Operations across the model lifecycle

Model family

Related models sharing a lineage, design, or release identity.

in: AI model landscape › Recognize model families

Model hub

A service hosting and organizing model files and documentation.

in: Local AI runtimes › Choose a runtime and application

Model license

Terms governing a model's use, modification, and distribution.

in: Model access and licensing › Access, weights, and the OSI definition

Model serving

Operating a model behind an interface that accepts inference requests and returns results.

in: Model serving › Model serving fundamentals

Multi-agent system

A system in which multiple agents interact or coordinate.

in: Agent memory and orchestration › Choose what to retain and coordinate

Multimodal model

A model that processes or generates more than one kind of data.

in: Multimodal AI › What counts as multimodal?

N

Narrow AI

Also: task-specific AI

AI designed or evaluated for a limited range of tasks.

in: AI foundations › What AI means

Natural language processing

Also: NLP

Computational methods for analyzing, understanding, or generating human language.

in: Natural language processing › Choose the language task

Neural network

Also: artificial neural network, ANN

A model made of connected layers of adjustable calculations.

in: Deep learning › How a neural network learns

Neuro-symbolic AI

Approaches that combine neural methods with symbolic approaches to computing and reasoning.

in: Symbolic and neuro-symbolic AI › Rules and expert systems

Next-token prediction

Estimating the next token from preceding context.

in: Large language models › From text to tokens and back

NPU

Also: neural processing unit

A processor designed to accelerate selected neural-network computations.

in: AI hardware › Processors, memory, and accelerator support

O

OAuth

A framework that lets a third-party application obtain limited access to an HTTP service, with a resource owner’s approval or on its own behalf.

in: AI integration standards › Choose the interface and control access

Object detection

Finding and labeling objects and their locations in visual data.

in: Computer vision › Match the task to the output

Occupational exposure

The extent to which a job’s tasks could be affected by a technology.

in: AI at work › What AI can change in a job

OCR

Also: optical character recognition

Converting text visible in an image into machine-readable text.

in: Computer vision › Match the task to the output

Ollama

As documented on 2026-10-09, software for managing and using models through local and cloud options.

in: Local AI runtimes › Choose a runtime and application

On-device AI

AI computation performed on the device handling the user's task.

in: Local and on-device AI › Where computation runs

Open weights

Also: open-weight model

Model parameters available for download; permissions depend on the license.

in: Model access and licensing › Access, weights, and the OSI definition

Open-source AI

An AI system that meets the OSI definition; downloadable weights alone do not show that it meets the definition.

in: Model access and licensing › Access, weights, and the OSI definition

Orchestration

Coordinating models, tools, state, and workflow steps.

in: Agent memory and orchestration › Choose what to retain and coordinate

Overfitting

Learning training-data quirks that do not carry over to new data.

in: Machine Learning › Fit, overfit, and generalize

P

Parameter-efficient fine-tuning

Also: PEFT

Adapting a model by training a limited set of parameters or added components.

in: Fine-tuning › Choose an adaptation method

Parameters

Also: model parameters

Adjustable numerical values learned during training.

in: Large language models › From text to tokens and back

Pass at k

Also: pass@k

The estimated chance that at least one of k generated attempts passes the evaluation tests.

in: AI benchmarks › What makes two scores comparable?

Perplexity

A measure of how uncertain a model is about observed tokens.

in: AI evaluation › Choose measures that fit the task

Personal data

Under the EU GDPR, which applies from 25 May 2018, personal data means information relating to an identified or identifiable natural person.

in: AI law and regulation › Find the law, status and date

Policy

A rule or model that specifies actions for an observed situation.

in: Reinforcement learning › The parts of a reward-based problem

Post-training

Training after a base model is created to change behavior or capabilities.

in: Foundation models › What kind of model is it?

Post-training quantization

Also: PTQ

Quantizing a model after its original training.

in: Model quantization › What fewer bits change

Precision

The share of predicted positive cases that are actually positive.

in: AI evaluation › Choose measures that fit the task

Prefill

The inference stage that processes the supplied prompt.

in: LLM inference and reasoning › Choose how the next token is selected

Pretraining

Initial training that develops broadly reusable model capabilities.

in: Foundation models › What kind of model is it?

Probability distribution

A description of how probability is assigned across possible outcomes.

in: Math for AI › Read vectors, matrices, and tensors

Prompt

Input supplied to a model to guide its response.

in: Prompting and context › Instructions, examples, and response shape

Prompt caching

Reusing computation for a matching prompt prefix in later requests.

in: Context engineering › What belongs in context

Prompt injection

Attacker-controlled input attempting to redirect a system from its intended instructions.

in: AI security › Threats in prompts and data

Q

Q4_K_M

A mixed-precision preset in llama.cpp's four-bit K-quant family.

in: Model quantization › What fewer bits change

QLoRA

Training LoRA adapters while keeping the base model quantized.

in: Fine-tuning › Choose an adaptation method

Quantization

Representing model values with fewer numerical bits.

in: Model quantization › What fewer bits change

R

RAM

Also: random-access memory

Working memory used by a running computer.

in: AI hardware › Processors, memory, and accelerator support

Random forest

A model combining predictions from multiple decision trees.

in: Predictive machine learning › Match the method to the output

Reasoning model

A model designed or trained to devote computation to multi-step problem solving.

in: Foundation models › What kind of model is it?

Reasoning tokens

Tokens used for intermediate reasoning; their accounting and visibility vary by system.

in: LLM inference and reasoning › Choose how the next token is selected

Recall

The share of actual positive cases successfully identified.

in: AI evaluation › Choose measures that fit the task

Recommender system

Also: recommendation system

A system selecting or ranking items for a user or situation.

in: Predictive machine learning › Match the method to the output

Recurrent neural network

Also: RNN

A network that carries an internal state between sequence steps.

in: Neural-network architectures › Architecture building blocks

Regression

Predicting a numerical value.

in: Predictive machine learning › Match the method to the output

Regularization

Constraints or penalties intended to reduce unnecessary model complexity.

in: Machine Learning › Fit, overfit, and generalize

Reinforcement learning

Also: RL

Learning action choices through feedback expressed as rewards.

in: Reinforcement learning › The parts of a reward-based problem

Reranker

A component reordering retrieved candidates by a relevance score.

in: Retrieval-augmented generation › The retrieval and answer pipeline

Retrieval-augmented generation

Also: RAG

Generating an answer using information retrieved from an external collection.

in: Retrieval-augmented generation › The retrieval and answer pipeline

Retriever

A component selecting potentially relevant information for a query.

in: Retrieval-augmented generation › The retrieval and answer pipeline

Reward

A signal expressing how desirable an action or outcome is.

in: Reinforcement learning › The parts of a reward-based problem

Reward hacking

Exploiting a reward measure without achieving its intended objective.

in: AI alignment › Goals, constraints and behavior

Reward model

A model that scores outputs according to a learned preference or objective.

in: Preference and reward training › Feedback, reward models, and optimization

RLAIF

Also: reinforcement learning from AI feedback

Reinforcement learning in which feedback supplied by AI systems provides the preference signal.

in: Preference and reward training › Feedback, reward models, and optimization

RLHF

Also: reinforcement learning from human feedback

Reinforcement learning in which rewards are derived from human feedback.

in: Preference and reward training › Feedback, reward models, and optimization

RLVR

Also: reinforcement learning with verifiable rewards

Reinforcement learning that uses rewards checked against defined criteria, such as matching a correct answer or passing code unit tests.

in: Preference and reward training › Feedback, reward models, and optimization

ROCm

AMD’s software stack for supported accelerator computing.

in: AI hardware › Processors, memory, and accelerator support

S

Safetensors

A tensor file format designed to avoid executable object deserialization.

in: Local AI runtimes › Choose a runtime and application

Sampling

Also: token sampling

Selecting an output token according to a probability distribution.

in: LLM inference and reasoning › Choose how the next token is selected

Sandbox

An isolated execution environment intended to limit permitted actions.

in: Tool use and automation › How a model calls a tool

Scaling law

An empirical relationship between resources and measured model performance.

in: Pretraining › Read scaling evidence

Segmentation

Assigning visual regions or pixels to meaningful categories or objects.

in: Computer vision › Match the task to the output

Self-attention

Attention that relates positions within the same input sequence.

in: Neural-network architectures › Architecture building blocks

Self-hosting

Also: self-hosted AI

Operating a service on infrastructure under your control.

in: Local and on-device AI › Where computation runs

Self-supervised learning

Learning from targets constructed from the input data itself.

in: Machine Learning › How models learn from data

Semantic search

Retrieval that uses represented meaning rather than matching only textual terms.

in: Embeddings and search › Representations and retrieval methods

Sim-to-real transfer

Applying learning from simulation to a physical environment.

in: Robot learning › Learning behavior and transferring it

Skills over MCP

An extension that exposes Agent Skills through MCP resources and related methods.

in: Model Context Protocol › Connection roles and server capabilities

Small language model

Also: SLM

A relatively small language model; the term does not specify a universal size cutoff.

in: Foundation models › What kind of model is it?

Speaker diarization

Detecting when speakers change and labeling the individual voices in audio.

in: Speech and audio AI › Choose the speech task and measure its output

Speculative decoding

A draft process proposes tokens that a target model verifies.

in: LLM inference and reasoning › Choose how the next token is selected

Standard input and output transport

Also: stdio transport

Communication with a process through its standard input and output streams.

in: Model Context Protocol › Connection roles and server capabilities

State-space model

Also: SSM

A sequence model that updates a compact internal state over time.

in: Neural-network architectures › Architecture building blocks

Streamable HTTP

In the 2026-07-28 specification, an HTTP-based transport in which a client sends each message as a POST and receives a JSON response or a request-scoped event stream.

in: Model Context Protocol › Connection roles and server capabilities

Structured output

Output constrained to a specified machine-readable structure.

in: Prompting and context › Instructions, examples, and response shape

Supervised fine-tuning

Also: SFT

Adapting a model by training it on examples that pair inputs with desired outputs.

in: Fine-tuning › Choose an adaptation method

Supervised learning

Learning from examples paired with target outputs.

in: Machine Learning › How models learn from data

SWE-bench

A benchmark family that evaluates software changes by asking a system to resolve repository issues.

in: AI benchmarks › What makes two scores comparable?

Sycophancy

Agreeing with a user's beliefs or preferences at the expense of accuracy.

in: AI alignment › Goals, constraints and behavior

Symbolic AI

Also: rule-based AI

AI that represents relevant knowledge explicitly with symbols and manipulates those representations using rules or other procedures.

in: Symbolic and neuro-symbolic AI › Rules and expert systems

Synthetic data

Artificially generated examples used instead of or alongside observed data.

in: Data for AI › Build a dataset and keep evaluation honest

System instruction

Also: system prompt

An application-supplied instruction with a designated priority that varies by system.

in: Prompting and context › Instructions, examples, and response shape

T

Task success rate

The share of trials meeting explicitly defined completion criteria.

in: Evaluating AI systems › Define tests and choose graders

Temperature

A setting that changes how concentrated the probabilities are when selecting a token.

in: LLM inference and reasoning › Choose how the next token is selected

Tensor

A numerical array that can have any number of dimensions.

in: Math for AI › Read vectors, matrices, and tensors

Test set

Held-out examples used to estimate performance after development choices.

in: Data for AI › Build a dataset and keep evaluation honest

Test-time compute

Also: inference-time compute

Computation spent while solving a problem rather than training the model.

in: LLM inference and reasoning › Choose how the next token is selected

Text to speech

Also: TTS

Generating spoken audio from text.

in: Speech and audio AI › Choose the speech task and measure its output

Throughput

The amount of work completed per unit of time, such as final responses or output tokens during a benchmark.

in: Model serving › Model serving fundamentals

Time to first token

Also: TTFT

Elapsed time from sending a request until the first streamed output is received; state the measurement boundaries.

in: Model serving › Model serving fundamentals

Token

A unit encoding model input or output, often a piece of a word.

in: Large language models › From text to tokens and back

Tokenizer

A procedure that converts text into a model's token identifiers.

in: Large language models › From text to tokens and back

Tokens per second

Also: tokens/s

A rate of token processing or generation, interpreted under the stated workload, measurement interval, and token-counting method.

in: Model serving › Model serving fundamentals

Tool calling

Also: function calling

A model requests a software operation with structured arguments for a host to execute.

in: Tool use and automation › How a model calls a tool

Top-k

Restricting token sampling to the k highest-probability candidates.

in: LLM inference and reasoning › Choose how the next token is selected

Top-p

Also: nucleus sampling

Sampling from the smallest set of likely candidates whose probabilities reach a chosen cumulative share.

in: LLM inference and reasoning › Choose how the next token is selected

Training

Adjusting a model using data or experience.

in: Machine Learning › How models learn from data

Training set

The examples used to adjust a model.

in: Data for AI › Build a dataset and keep evaluation honest

Transfer learning

Applying learning from one setting to another task or domain.

in: Machine Learning › How models learn from data

Transformer

A neural-network architecture that uses attention to update representations.

in: Neural-network architectures › Architecture building blocks

Turing test

Also: imitation game

A historical test based on whether conversation can distinguish a machine from a person.

in: History of AI › Milestones and tests

U

Underfitting

Failing to capture useful patterns even in the training data.

in: Machine Learning › Fit, overfit, and generalize

Unified memory

A memory arrangement allowing processors to share a common memory pool.

in: AI hardware › Processors, memory, and accelerator support

Unsupervised learning

Finding patterns in data without supplied target outputs.

in: Machine Learning › How models learn from data

V

Validation set

Also: development set

Examples used to choose settings or compare development decisions.

in: Data for AI › Build a dataset and keep evaluation honest

Vector

An ordered collection of numbers representing a quantity or item.

in: Math for AI › Read vectors, matrices, and tensors

Vector database

A datastore that stores vector representations and supports similarity search.

in: Embeddings and search › Representations and retrieval methods

Vector index

A data structure that organizes vectors to speed up searches among them.

in: Embeddings and search › Representations and retrieval methods

Vibe coding

A loosely defined practice of building software through heavy AI generation.

in: AI for coding › Use assistance without losing the thread

Vision-language model

Also: VLM

A model that connects visual information with language, for example by aligning image and text representations.

in: Multimodal AI › What counts as multimodal?

Vision-language-action model

Also: VLA

A model that uses visual and language information to produce actions for controlling a robot.

in: Embodied AI › What makes AI embodied?

vLLM

As checked on 2026-10-09, vLLM is an inference and serving engine for language models.

in: Model serving › Model serving fundamentals

Voice cloning

Generating speech that resembles a reference person's voice.

in: Speech and audio AI › Choose the speech task and measure its output

VRAM

Also: video memory

Memory directly available to a graphics processor.

in: AI hardware › Processors, memory, and accelerator support

W

Water footprint

Direct and indirect water use attributed to an activity within stated boundaries.

in: AI environmental impact › What does a footprint include?

Watermarking

Embedding a detectable signal in content to indicate origin or ownership.

in: AI media and information › What provenance can tell you

Weights

Also: model weights

Learned coefficients, often used loosely to refer to all model parameters.

in: Large language models › From text to tokens and back

Word error rate

Also: WER

Transcription errors measured relative to the number of reference words.

in: Speech and audio AI › Choose the speech task and measure its output

World model

A learned representation that predicts how an environment evolves under actions.

in: World models and simulation › Simulation, models, and digital twins

Z

Zero-shot prompting

Requesting a task without supplying worked examples.

in: Prompting and context › Instructions, examples, and response shape

Questions and comments