AI Glossary
A plain-English reference for the 120 terms that show up most in our AI tool reviews — from agents and embeddings to retrieval-augmented generation. Each entry is written by our editors and updated monthly.
A20 entries
Agent
Agents & toolsAn AI system that can take actions, use tools, and make decisions autonomously to complete a goal. Read about Agent →
AGI
Core conceptsArtificial General Intelligence — a hypothetical AI that matches or exceeds human ability across virtually any intellectual task. Read about AGI →
AI
Core conceptsArtificial Intelligence — software that performs tasks normally requiring human intelligence, like understanding language, recognising images, or generating content. Read about AI →
AI Assistant
Core conceptsA conversational AI tool that helps users with tasks like writing, scheduling, research, or answering questions in natural language. Read about AI Assistant →
Alignment
SafetyThe challenge of making AI systems behave in ways that match human values and intentions — not just their literal instructions. Read about Alignment →
API
Infra & costAn interface that lets developers send requests to an AI model and get responses programmatically — the way most AI tools talk to LLMs. Read about API →
Adversarial Attack
SafetyDeliberately crafted inputs that trick an AI model into producing wrong or harmful outputs — a key category of AI security threat. Read about Adversarial Attack →
Agent Harness
Agents & toolsThe scaffolding around an LLM — tools, memory, loops, and orchestration — that turns a model into an agent. Read about Agent Harness →
Agent Orchestration
Agents & toolsThe coordination layer that decides which agent or tool runs next, manages state across steps, and handles failures in multi-step AI workflows. Read about Agent Orchestration →
Agent Swarm
Agents & toolsA group of AI agents that work together — often with different roles — to solve a problem one agent could not handle alone. Read about Agent Swarm →
Agentic AI
Agents & toolsAI systems designed to act, not just respond — they plan, use tools, and make decisions across multiple steps to complete a goal. Read about Agentic AI →
Agentic Workflow
Agents & toolsA multi-step task where an AI agent autonomously decides the steps, uses tools as needed, and works toward a goal with minimal human steering. Read about Agentic Workflow →
AI Agent
Agents & toolsSoftware that uses an LLM to plan and act — picking tools, taking actions, and adapting based on results to complete a user’s goal. Read about AI Agent →
AI Avatar
ModalitiesA photorealistic or stylised digital character driven by AI — used for video presenters, customer service, training, and marketing. Read about AI Avatar →
AI Evaluation
TrainingThe structured process of measuring how well an AI model performs — accuracy, safety, cost, latency — usually with a fixed test set called an eval. Read about AI Evaluation →
AI Native
Core conceptsA product designed from the ground up around AI capabilities — as opposed to bolting AI features onto an existing app. Read about AI Native →
AI Overview
Data & retrievalGoogle’s AI-generated answer summary at the top of search results — synthesised from multiple sources, replacing some traditional blue-link traffic. Read about AI Overview →
AI Search
Data & retrievalA search experience that returns a synthesised AI answer with citations — instead of a ranked list of links — powered by retrieval plus an LLM. Read about AI Search →
AI Wrapper
Core conceptsA product whose value is mostly a thin UI over someone else’s foundation model — often used as a critique, sometimes as a description. Read about AI Wrapper →
Autonomous Agent
Agents & toolsAn AI agent that operates with minimal human oversight — making and executing decisions independently across long time horizons. Read about Autonomous Agent →
B3 entries
Benchmark
TrainingA standardised test used to compare AI models on specific tasks — like coding, maths, reasoning, or following instructions. Read about Benchmark →
Bias
SafetyWhen an AI model's outputs systematically reflect unfair patterns from its training data — about gender, race, age, or other groups. Read about Bias →
Browser Agent
Agents & toolsAn AI agent that controls a real web browser — clicking, typing, and reading pages — to complete tasks on websites that lack APIs. Read about Browser Agent →
C11 entries
Chain of Thought
PromptingA prompting technique where you ask the AI to "think step by step" before giving an answer — usually leading to better reasoning. Read about Chain of Thought →
Chatbot
Core conceptsA program that simulates conversation with users — increasingly powered by LLMs to handle natural-language questions and tasks. Read about Chatbot →
Computer Vision
ModalitiesAI that can interpret images and video — recognising objects, reading text, detecting faces, or describing scenes. Read about Computer Vision →
Context Window
Core conceptsThe maximum amount of text (tokens) an AI model can read and remember at once during a single conversation. Read about Context Window →
Conversational AI
Core conceptsAI systems designed for natural back-and-forth dialogue with users — covering chatbots, voice assistants, and AI agents. Read about Conversational AI →
Copilot
Agents & toolsAn AI assistant embedded directly into a workflow — like coding, writing, or design — that suggests, completes, or generates work alongside the user. Read about Copilot →
Code Generation
ModalitiesUsing an AI model to write source code from a natural-language description, a partial snippet, or a test. Read about Code Generation →
Code Interpreter
Agents & toolsA sandboxed code-execution tool an AI agent can call to run scripts, do math, analyse files, or generate charts on the fly. Read about Code Interpreter →
Coding Agent
Agents & toolsAn AI agent specialised for writing, editing, and debugging code — usually with the ability to read your repo, run tests, and open pull requests. Read about Coding Agent →
Computer Use
Agents & toolsThe capability for an AI model to control a computer the way a human does — moving the mouse, clicking, typing, reading the screen. Read about Computer Use →
Constitutional AI
SafetyAn Anthropic-pioneered training method that teaches a model to critique and rewrite its own outputs against a written set of principles (a constitution). Read about Constitutional AI →
D7 entries
Deep Learning
TrainingA type of machine learning that uses layered neural networks to learn complex patterns — the foundation of modern AI. Read about Deep Learning →
Deepfake
SafetyAI-generated media — usually video or audio — that convincingly impersonates a real person saying or doing something they didn't. Read about Deepfake →
Diffusion Model
ModalitiesThe type of AI model behind most modern image and video generators — it learns to create content by reversing a noising process. Read about Diffusion Model →
Distillation
TrainingTraining a smaller, cheaper AI model to mimic the outputs of a larger, more capable one — preserving most of the quality at a fraction of the cost. Read about Distillation →
Data Poisoning
SafetyAn attack that corrupts a model’s training data to make it behave incorrectly — either degrading performance or installing hidden backdoors. Read about Data Poisoning →
Deep Research
Agents & toolsAn AI agent feature that spends minutes (not seconds) browsing many sources, reasoning across them, and producing a long-form cited report. Read about Deep Research →
DPO
TrainingDirect Preference Optimization — a simpler alternative to RLHF that fine-tunes a model directly on preference pairs, no separate reward model required. Read about DPO →
E3 entries
Embeddings
Data & retrievalA way of converting text (or images) into lists of numbers so an AI can measure how similar two pieces of content are. Read about Embeddings →
Embodied AI
ModalitiesAI that operates a physical body — usually a robot — using vision, language, and motor control to act in the real world. Read about Embodied AI →
Extended Thinking
Core conceptsA model mode where the LLM spends extra compute reasoning through a problem before answering — trading latency for quality on hard tasks. Read about Extended Thinking →
F4 entries
Few-shot Learning
PromptingA prompting technique where you include a handful of examples in the prompt so the AI learns the pattern you want it to follow. Read about Few-shot Learning →
Fine-tuning
TrainingFurther training a pre-trained AI model on your own data to specialise it for a specific task or style. Read about Fine-tuning →
Foundation Model
Core conceptsA large, general-purpose AI model trained on broad data that can be adapted (via prompting or fine-tuning) to many downstream tasks. Read about Foundation Model →
Function Calling
Agents & toolsA feature that lets an AI model trigger specific functions or APIs in your app instead of just returning text. Read about Function Calling →
G5 entries
Generative AI
Core conceptsAI systems that create new content — text, images, audio, video, or code — rather than just classifying or predicting from existing data. Read about Generative AI →
GPT
Core conceptsGenerative Pre-trained Transformer — the architecture behind OpenAI's models, and now used as shorthand for any LLM-powered chatbot. Read about GPT →
Guardrails
SafetyRules and filters that constrain what an AI model can output — used to block harmful, off-topic, or non-compliant responses. Read about Guardrails →
Generative Search
Data & retrievalA search experience that generates an answer in natural language — using retrieved sources as input to an LLM — instead of returning a list of links. Read about Generative Search →
Generative UI
ModalitiesA user interface where AI generates UI elements — components, layouts, even whole pages — in response to what the user is doing or asking. Read about Generative UI →
H2 entries
Hallucination
SafetyWhen an AI confidently states something that is factually wrong or completely made up. Read about Hallucination →
Human in the Loop
Agents & toolsAn AI workflow that pauses for a human to review, approve, or correct the model’s output at key steps — instead of running fully autonomously. Read about Human in the Loop →
I1 entry
Inference
Infra & costThe process of running a trained AI model to generate a response — as opposed to training the model. Read about Inference →
J1 entry
Jailbreak
SafetyA prompt or technique that tricks an AI model into ignoring its safety rules and producing content it would normally refuse. Read about Jailbreak →
K4 entries
Knowledge Base
Data & retrievalA structured collection of documents an AI system can search and quote — the source-of-truth corpus that grounds RAG and many AI agents. Read about Knowledge Base →
Knowledge Distillation
TrainingTraining a small "student" model to imitate a large "teacher" model — capturing most of the teacher’s capability at a fraction of the size and cost. Read about Knowledge Distillation →
Knowledge Graph
Data & retrievalA structured representation of entities and the relationships between them — used to give AI systems explicit, queryable facts. Read about Knowledge Graph →
KV Cache
Infra & costAn inference-time cache that stores intermediate attention computations so a model doesn’t re-process its earlier tokens on every new token. Read about KV Cache →
L3 entries
Latency
Infra & costThe time it takes an AI model to respond to a request — from when you hit send to when the first or final word appears. Read about Latency →
LLM
Core conceptsLarge Language Model — the type of AI behind tools like ChatGPT and Claude, trained to understand and generate text. Read about LLM →
LoRA
TrainingLow-Rank Adaptation — a cheap way to fine-tune large AI models by training a small set of extra weights instead of the whole model. Read about LoRA →
M5 entries
Machine Learning
Core conceptsA type of AI where systems learn patterns from data rather than being explicitly programmed with rules. Read about Machine Learning →
MCP
Agents & toolsModel Context Protocol — an open standard that lets AI models connect to external tools and data sources in a consistent way. Read about MCP →
Multi-modal
ModalitiesAn AI model that can understand and work with multiple types of input — text, images, audio, or video — not just text. Read about Multi-modal →
Mixture of Experts
Core conceptsA model architecture that has many "expert" subnetworks but activates only a few per token — getting big-model quality at small-model inference cost. Read about Mixture of Experts →
Multi-Agent System
Agents & toolsAn AI architecture where multiple agents — often with different roles, models, or tools — collaborate on a task one agent could not handle alone. Read about Multi-Agent System →
N4 entries
Natural Language Processing
Core conceptsThe branch of AI focused on understanding, generating, and working with human language — covering everything from spell-check to ChatGPT. Read about Natural Language Processing →
Neural Network
TrainingA computing system inspired by the brain, made up of layers of connected "neurons" that learn patterns from data — the building block of modern AI. Read about Neural Network →
No-Code AI
Core conceptsAI tools and platforms that let non-developers build AI-powered apps and workflows through visual interfaces instead of writing code. Read about No-Code AI →
Named Entity Recognition
Data & retrievalAn NLP task that identifies and labels names of people, places, organisations, dates, and other specific entities in text. Read about Named Entity Recognition →
O2 entries
OCR
ModalitiesOptical Character Recognition — AI that converts text inside images, scanned documents, or PDFs into editable, searchable text. Read about OCR →
Open-weight Model
TrainingAn AI model whose trained weights are publicly released, so anyone can download, run, or fine-tune it themselves. Read about Open-weight Model →
P5 entries
Prompt Caching
Infra & costA feature that stores parts of a prompt the model has already processed, making repeat or follow-up requests much faster and cheaper. Read about Prompt Caching →
Prompt Engineering
PromptingThe practice of crafting inputs to an AI model carefully to get better, more reliable outputs. Read about Prompt Engineering →
Prompt Injection
SafetyA security attack where malicious instructions hidden in user input or external content trick an AI model into ignoring its real instructions. Read about Prompt Injection →
Post-training
TrainingEverything done to a model after pretraining — fine-tuning, RLHF, DPO, safety training — to turn a raw base model into a usable product. Read about Post-training →
Pre-training
TrainingThe first and most expensive phase of building a model — learning language and world knowledge by predicting the next token across trillions of words. Read about Pre-training →
Q1 entry
Quantization
Infra & costShrinking an AI model by storing its weights in lower-precision numbers — making it smaller, faster, and cheaper with minimal quality loss. Read about Quantization →
R7 entries
RAG
Data & retrievalRetrieval-Augmented Generation — a technique that gives an AI model access to external documents before it answers, so it can cite real, up-to-date sources. Read about RAG →
RLHF
TrainingReinforcement Learning from Human Feedback — the training technique that teaches AI models to be helpful, harmless, and honest. Read about RLHF →
Rate Limit
Infra & costA cap on how many requests or tokens a user can send to an AI API in a given window — used to manage cost, capacity, and abuse. Read about Rate Limit →
ReAct
Agents & toolsAn agent pattern that interleaves "reasoning" steps with "acting" steps — letting the model think out loud, take an action, observe, and reason again. Read about ReAct →
Reasoning Model
Core conceptsA model variant trained or tuned to spend more compute on internal reasoning before answering — better on math, code, and multi-step problems. Read about Reasoning Model →
Red Teaming
SafetyDeliberately trying to make an AI model misbehave — find jailbreaks, exploits, and failure modes — before adversaries do. Read about Red Teaming →
RLAIF
TrainingReinforcement Learning from AI Feedback — alignment training where another AI model, not a human, provides the preference signal used to fine-tune the target model. Read about RLAIF →
S11 entries
Semantic Search
Data & retrievalSearch that finds results by meaning rather than exact keyword matches — so "car" finds results about "automobile" too. Read about Semantic Search →
Speech-to-Text
ModalitiesAI that converts spoken audio into written text — the technology behind voice assistants, transcription tools, and meeting recorders. Read about Speech-to-Text →
Streaming
Infra & costSending an AI model's response token-by-token as it's generated, so the user sees text appear immediately instead of waiting for the full reply. Read about Streaming →
System Prompt
PromptingThe high-level instructions given to an AI model at the start of a conversation that define its role, behaviour, and constraints. Read about System Prompt →
Sandbox
Infra & costAn isolated execution environment where AI-generated code or agent actions can run without affecting the host system. Read about Sandbox →
Sentiment Analysis
Data & retrievalAn NLP task that classifies text as positive, negative, or neutral — used at scale for reviews, support tickets, social media, and survey responses. Read about Sentiment Analysis →
Small Language Model
Core conceptsA compact language model — typically 1B to 15B parameters — designed to run cheaply, fast, or on-device while still being useful for focused tasks. Read about Small Language Model →
Structured Output
PromptingForcing an LLM to return data in a specific format — usually JSON matching a schema — so downstream code can parse it reliably. Read about Structured Output →
Summarization
ModalitiesCompressing a longer text — a meeting transcript, an article, a chat thread — into a shorter version that keeps the key information. Read about Summarization →
Superintelligence
Core conceptsA hypothetical AI that dramatically exceeds human cognitive ability across every domain — beyond AGI on the capability scale. Read about Superintelligence →
Synthetic Data
TrainingAI-generated training data — used when real data is scarce, expensive, sensitive, or simply not high-enough quality. Read about Synthetic Data →
T11 entries
Temperature
PromptingA setting that controls how random or creative an AI model's responses are — lower values produce focused answers, higher values produce more varied ones. Read about Temperature →
Text-to-Image
ModalitiesAI that generates new images from a written description — the technology behind tools like Midjourney, DALL-E, and Stable Diffusion. Read about Text-to-Image →
Text-to-Speech
ModalitiesAI that converts written text into natural-sounding spoken audio — used for narration, accessibility, voice assistants, and content creation. Read about Text-to-Speech →
Text-to-Video
ModalitiesAI that generates video clips from a text description — the next frontier after text-to-image, with rapidly improving quality. Read about Text-to-Video →
Tokens
Core conceptsThe basic units of text that AI models read and write — roughly ¾ of a word each. Models are priced and limited by token count. Read about Tokens →
Tool Use
Agents & toolsThe ability of an AI model to call external tools — like a calculator, search engine, or API — to help answer a question. Read about Tool Use →
Training Data
TrainingThe dataset an AI model learns from — its quality, diversity, and biases directly shape what the model can do and how well it does it. Read about Training Data →
Transformer
TrainingThe neural network architecture introduced in 2017 that powers nearly every modern LLM, image generator, and AI breakthrough. Read about Transformer →
Test-time Compute
Core conceptsThe amount of compute spent at inference time on a single response — increased dramatically by reasoning models to improve quality. Read about Test-time Compute →
Top-k Sampling
PromptingA decoding strategy that picks the next token only from the top K most likely candidates — trading diversity for focus. Read about Top-k Sampling →
Top-p Sampling
PromptingA decoding strategy (also called nucleus sampling) that picks the next token from the smallest set of candidates whose cumulative probability exceeds P. Read about Top-p Sampling →
V5 entries
Vector Database
Data & retrievalA database optimised for storing and searching embeddings (numerical representations of text or images) by similarity. Read about Vector Database →
Voice Cloning
ModalitiesAI that learns to mimic a specific person's voice from a short sample, then generates new speech in that voice from any text. Read about Voice Cloning →
Vibe Coding
Core conceptsA 2025–26 coined term for writing software by chatting with an AI agent — describing the vibe of what you want and accepting whatever code it generates. Read about Vibe Coding →
Vision-Language Model
ModalitiesA multimodal model that processes both images and text — letting you ask questions about an image, generate captions, or reason over visual content. Read about Vision-Language Model →
Voice Agent
Agents & toolsA real-time conversational AI you talk to — over the phone, in an app, or through a wearable — that listens, reasons, and replies in voice. Read about Voice Agent →
W4 entries
Workflow Automation
Agents & toolsAI-powered tools that chain together multiple steps — apps, APIs, and AI models — to automate end-to-end business processes. Read about Workflow Automation →
Watermarking
SafetyEmbedding a hidden, machine-detectable signal in AI-generated content so it can later be identified as AI-made. Read about Watermarking →
Webhook
Infra & costAn HTTP callback an AI service makes to your endpoint when a long-running event completes — async results, agent updates, batch jobs. Read about Webhook →
World Model
Core conceptsA model that learns to simulate how the world (or a specific environment) evolves — predicting what happens next given an action. Read about World Model →
Z1 entry
Zero-shot Learning
PromptingAsking an AI model to perform a task with no examples in the prompt — relying entirely on its general training. Read about Zero-shot Learning →
Last reviewed May 2026 · Edited by the ToolDirectory editorial team