ToolDirectory.AI · Reference

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.

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120 of 120 terms

A20 entries

Agent

Agents & tools

An AI system that can take actions, use tools, and make decisions autonomously to complete a goal. Read about Agent

AGI

Core concepts

Artificial General Intelligence — a hypothetical AI that matches or exceeds human ability across virtually any intellectual task. Read about AGI

AI

Core concepts

Artificial Intelligence — software that performs tasks normally requiring human intelligence, like understanding language, recognising images, or generating content. Read about AI

AI Assistant

Core concepts

A conversational AI tool that helps users with tasks like writing, scheduling, research, or answering questions in natural language. Read about AI Assistant

Alignment

Safety

The challenge of making AI systems behave in ways that match human values and intentions — not just their literal instructions. Read about Alignment

API

Infra & cost

An 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

Safety

Deliberately 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 & tools

The scaffolding around an LLM — tools, memory, loops, and orchestration — that turns a model into an agent. Read about Agent Harness

Agent Orchestration

Agents & tools

The 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 & tools

A 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 & tools

AI 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 & tools

A 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 & tools

Software 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

Modalities

A photorealistic or stylised digital character driven by AI — used for video presenters, customer service, training, and marketing. Read about AI Avatar

AI Evaluation

Training

The 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 concepts

A 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 & retrieval

Google’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 Wrapper

Core concepts

A 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 & tools

An AI agent that operates with minimal human oversight — making and executing decisions independently across long time horizons. Read about Autonomous Agent

B3 entries

Benchmark

Training

A standardised test used to compare AI models on specific tasks — like coding, maths, reasoning, or following instructions. Read about Benchmark

Bias

Safety

When 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 & tools

An 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

Prompting

A 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 concepts

A program that simulates conversation with users — increasingly powered by LLMs to handle natural-language questions and tasks. Read about Chatbot

Computer Vision

Modalities

AI that can interpret images and video — recognising objects, reading text, detecting faces, or describing scenes. Read about Computer Vision

Context Window

Core concepts

The 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 concepts

AI systems designed for natural back-and-forth dialogue with users — covering chatbots, voice assistants, and AI agents. Read about Conversational AI

Copilot

Agents & tools

An 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

Modalities

Using 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 & tools

A 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 & tools

An 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 & tools

The 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

Safety

An 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

Training

A type of machine learning that uses layered neural networks to learn complex patterns — the foundation of modern AI. Read about Deep Learning

Deepfake

Safety

AI-generated media — usually video or audio — that convincingly impersonates a real person saying or doing something they didn't. Read about Deepfake

Diffusion Model

Modalities

The 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

Training

Training 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

Safety

An 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 & tools

An 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

Training

Direct 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 & retrieval

A 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

Modalities

AI 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 concepts

A 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

Prompting

A 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

Training

Further 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 concepts

A 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 & tools

A 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 concepts

AI 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 concepts

Generative Pre-trained Transformer — the architecture behind OpenAI's models, and now used as shorthand for any LLM-powered chatbot. Read about GPT

Guardrails

Safety

Rules and filters that constrain what an AI model can output — used to block harmful, off-topic, or non-compliant responses. Read about Guardrails

Generative UI

Modalities

A 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

Safety

When an AI confidently states something that is factually wrong or completely made up. Read about Hallucination

Human in the Loop

Agents & tools

An 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 & cost

The process of running a trained AI model to generate a response — as opposed to training the model. Read about Inference

J1 entry

Jailbreak

Safety

A 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 & retrieval

A 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

Training

Training 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 & retrieval

A structured representation of entities and the relationships between them — used to give AI systems explicit, queryable facts. Read about Knowledge Graph

KV Cache

Infra & cost

An 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 & cost

The 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 concepts

Large Language Model — the type of AI behind tools like ChatGPT and Claude, trained to understand and generate text. Read about LLM

LoRA

Training

Low-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 concepts

A type of AI where systems learn patterns from data rather than being explicitly programmed with rules. Read about Machine Learning

MCP

Agents & tools

Model 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

Modalities

An 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 concepts

A 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 & tools

An 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 concepts

The 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

Training

A 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 concepts

AI 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 & retrieval

An 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

Modalities

Optical Character Recognition — AI that converts text inside images, scanned documents, or PDFs into editable, searchable text. Read about OCR

Open-weight Model

Training

An 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 & cost

A 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

Prompting

The practice of crafting inputs to an AI model carefully to get better, more reliable outputs. Read about Prompt Engineering

Prompt Injection

Safety

A 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

Training

Everything 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

Training

The 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 & cost

Shrinking 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 & retrieval

Retrieval-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

Training

Reinforcement Learning from Human Feedback — the training technique that teaches AI models to be helpful, harmless, and honest. Read about RLHF

Rate Limit

Infra & cost

A 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 & tools

An 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 concepts

A 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

Safety

Deliberately trying to make an AI model misbehave — find jailbreaks, exploits, and failure modes — before adversaries do. Read about Red Teaming

RLAIF

Training

Reinforcement 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

Speech-to-Text

Modalities

AI that converts spoken audio into written text — the technology behind voice assistants, transcription tools, and meeting recorders. Read about Speech-to-Text

Streaming

Infra & cost

Sending 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

Prompting

The 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 & cost

An isolated execution environment where AI-generated code or agent actions can run without affecting the host system. Read about Sandbox

Sentiment Analysis

Data & retrieval

An 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 concepts

A 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

Prompting

Forcing 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

Modalities

Compressing 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 concepts

A hypothetical AI that dramatically exceeds human cognitive ability across every domain — beyond AGI on the capability scale. Read about Superintelligence

Synthetic Data

Training

AI-generated training data — used when real data is scarce, expensive, sensitive, or simply not high-enough quality. Read about Synthetic Data

T11 entries

Temperature

Prompting

A 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

Modalities

AI 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

Modalities

AI 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

Modalities

AI 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 concepts

The 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 & tools

The 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

Training

The 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

Training

The neural network architecture introduced in 2017 that powers nearly every modern LLM, image generator, and AI breakthrough. Read about Transformer

Test-time Compute

Core concepts

The 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

Prompting

A 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

Prompting

A 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 & retrieval

A database optimised for storing and searching embeddings (numerical representations of text or images) by similarity. Read about Vector Database

Voice Cloning

Modalities

AI 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 concepts

A 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

Modalities

A 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 & tools

A 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 & tools

AI-powered tools that chain together multiple steps — apps, APIs, and AI models — to automate end-to-end business processes. Read about Workflow Automation

Watermarking

Safety

Embedding a hidden, machine-detectable signal in AI-generated content so it can later be identified as AI-made. Read about Watermarking

Webhook

Infra & cost

An 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 concepts

A 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

Prompting

Asking 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

Vol. 4 · Issue 19 · Last reviewed 2026-05-30

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