The AI Glossary
Plain-English definitions for every AI term you'll encounter — whether you're just starting out or already building with AI. No jargon, no assumed knowledge.
Showing 62 of 62 terms
Agent (AI Agent)
Core AIAn AI system that can autonomously perceive its environment, make decisions, and take actions to achieve a specified goal — often by using tools, browsing the web, or writing and executing code.
In plain English: Think of it as an AI that doesn't just answer questions — it actually goes and does things for you, like booking a meeting or researching a topic end-to-end.
Example: An AI agent given the task 'research the top 5 CRM tools and send me a summary email' would search the web, compile the results, and send the email — all without you doing anything else.
Alignment
Ethics & SafetyThe challenge of ensuring that an AI system's goals, values, and behaviour match what its designers and users actually intend — especially as AI becomes more capable.
In plain English: Making sure the AI does what you actually want, not just what you literally asked for. A misaligned AI might technically follow instructions while causing unintended harm.
API (Application Programming Interface)
TechnicalA set of rules and protocols that allows one software application to communicate with another. AI companies expose APIs so developers can integrate their models into their own products.
In plain English: An API is like a waiter in a restaurant — you tell it what you want, it goes to the kitchen (the AI model), and brings back the result. You never see the kitchen.
Example: OpenAI's API lets developers send text to GPT-4 and receive a response, enabling them to build their own chatbots or writing tools.
Attention Mechanism
TechnicalA component of neural networks that allows a model to focus on the most relevant parts of an input when generating an output — the core innovation behind the Transformer architecture.
In plain English: When you read a sentence, you naturally focus on the most important words. Attention lets AI do the same thing — giving more 'weight' to relevant words when figuring out what to say next.
Autonomous AI
Core AIAI systems capable of operating independently to complete complex, multi-step tasks without continuous human oversight or instruction.
In plain English: AI that can work on its own for extended periods — more like hiring a contractor than asking someone a question.
Benchmark
TechnicalA standardised test or dataset used to measure and compare the performance of AI models across specific tasks, such as reasoning, coding, or language understanding.
In plain English: Like a standardised exam for AI — it lets researchers compare different models fairly by testing them on the same questions.
Example: MMLU (Massive Multitask Language Understanding) tests AI knowledge across 57 subjects including law, medicine, and history.
Bias (AI Bias)
Ethics & SafetySystematic errors in AI outputs caused by flawed assumptions, unrepresentative training data, or design choices that result in unfair or skewed results for certain groups.
In plain English: If an AI was trained mostly on data from one type of person or culture, it may give worse results for everyone else — like a spell-checker that only knows American English.
Chain-of-Thought (CoT)
LLMs & ModelsA prompting technique that encourages a language model to reason step-by-step before giving a final answer, significantly improving performance on complex reasoning tasks.
In plain English: Instead of asking an AI to jump straight to an answer, you ask it to 'think out loud' — this usually leads to much better results on hard problems.
Example: Adding 'Let's think step by step' to a maths problem prompt can dramatically improve accuracy.
Chatbot
AI ToolsA software application designed to simulate conversation with humans, typically via text or voice. Modern AI chatbots use large language models to generate contextually relevant responses.
In plain English: A computer program you can have a conversation with. Older chatbots followed rigid scripts; modern ones like ChatGPT can discuss almost anything.
Claude
LLMs & ModelsA family of large language models developed by Anthropic, designed with a focus on safety, helpfulness, and harmlessness. Claude is a leading competitor to OpenAI's GPT models.
In plain English: Claude is Anthropic's AI assistant — known for being thoughtful, nuanced, and particularly good at long documents and careful reasoning.
Constitutional AI
Ethics & SafetyA technique developed by Anthropic where an AI model is trained to critique and revise its own outputs based on a set of principles (a 'constitution'), reducing harmful outputs without relying solely on human feedback.
In plain English: Teaching an AI to self-correct by giving it a set of values and asking it to check its own answers against them — like a code of conduct for AI.
Context Window
LLMs & ModelsThe maximum amount of text (measured in tokens) that a language model can process in a single interaction — including both the input prompt and the generated output.
In plain English: Think of it as the AI's short-term memory. A larger context window means it can read and remember more of your conversation or document at once.
Example: GPT-4 Turbo has a 128,000-token context window — roughly equivalent to a 100,000-word book.
Copilot
AI ToolsAn AI assistant designed to work alongside a human in a specific workflow — most commonly in coding (GitHub Copilot) or productivity software (Microsoft Copilot). It suggests, completes, or generates content in context.
In plain English: An AI that sits next to you while you work and offers helpful suggestions — like autocomplete on steroids.
Deep Learning
Core AIA subset of machine learning that uses neural networks with many layers (hence 'deep') to learn representations of data. It is the foundation of most modern AI breakthroughs in image recognition, language, and speech.
In plain English: The technology behind most modern AI. It works by feeding enormous amounts of data through layers of virtual 'neurons' until the system learns to recognise patterns.
Diffusion Model
TechnicalA class of generative AI models that learn to create images (or other data) by learning to reverse a process of adding noise. Used by Stable Diffusion, DALL-E, and Midjourney.
In plain English: Imagine starting with pure static on a TV screen and gradually 'cleaning' it until a clear image appears. That's roughly how diffusion models generate images.
Embedding
TechnicalA numerical representation of text, images, or other data as a vector (a list of numbers) that captures semantic meaning, allowing AI models to compare and reason about concepts mathematically.
In plain English: A way of turning words or sentences into numbers so a computer can measure how similar two pieces of text are. 'King' and 'Queen' would have similar embeddings.
Emergent Behaviour
Core AICapabilities that appear in large AI models that were not explicitly trained for and were not present in smaller versions of the same model — often surprising even the researchers who built them.
In plain English: Unexpected abilities that 'emerge' as AI gets bigger — like a model suddenly being able to do maths or translate languages it was never specifically taught.
Few-Shot Learning
LLMs & ModelsA prompting approach where you provide a language model with a small number of examples (typically 2–10) of the desired input-output format before asking it to complete a new task.
In plain English: Showing the AI a few examples of what you want before asking it to do the task. Like showing a new employee two or three completed forms before asking them to fill one out.
Fine-Tuning
TechnicalThe process of further training a pre-trained AI model on a smaller, task-specific dataset to adapt it for a particular use case or domain.
In plain English: Taking a general-purpose AI and giving it extra training on your specific topic — like a doctor who completed general medical school and then did a specialist residency.
Foundation Model
Core AIA large AI model trained on broad, diverse data that can be adapted for a wide range of downstream tasks. GPT-4, Claude, and Gemini are all foundation models.
In plain English: A powerful, general-purpose AI model that serves as a starting point. Think of it as a highly educated generalist that can be specialised for almost any job.
Gemini
LLMs & ModelsGoogle DeepMind's family of multimodal large language models, designed to process and generate text, images, audio, and video. Gemini Ultra is Google's most capable model.
In plain English: Google's AI model — it can understand text, images, and more, and is integrated into Google products like Search, Docs, and Gmail.
Generative AI
Core AIAI systems that can create new content — including text, images, audio, video, and code — rather than simply analysing or classifying existing data.
In plain English: AI that makes things. ChatGPT writes text, Midjourney creates images, Suno generates music — all of these are generative AI tools.
GPT (Generative Pre-trained Transformer)
LLMs & ModelsA family of large language models developed by OpenAI, trained using a combination of unsupervised pre-training on large text corpora and reinforcement learning from human feedback. GPT-4 is the current flagship model.
In plain English: The technology behind ChatGPT. GPT models are trained on vast amounts of text from the internet and books, giving them broad knowledge and language ability.
GPU (Graphics Processing Unit)
TechnicalA specialised processor originally designed for rendering graphics, now widely used for training and running AI models due to its ability to perform many parallel calculations simultaneously.
In plain English: The hardware that makes AI possible. Training a large AI model requires thousands of GPUs running for weeks — which is why it costs so much.
Guardrails
Ethics & SafetySafety mechanisms built into AI systems to prevent them from generating harmful, offensive, or dangerous content — including content filters, output classifiers, and constitutional constraints.
In plain English: The rules and filters that stop an AI from saying things it shouldn't. Like parental controls, but for AI outputs.
Hallucination
LLMs & ModelsWhen an AI language model generates information that sounds plausible and confident but is factually incorrect or entirely fabricated — a significant reliability challenge for current LLMs.
In plain English: When an AI makes things up and presents them as facts. It might confidently cite a book that doesn't exist or give you a wrong date for a historical event.
Example: An AI asked to cite sources might invent realistic-sounding academic paper titles and authors that don't actually exist.
Human-in-the-Loop (HITL)
Ethics & SafetyA system design approach where human oversight or approval is required at key decision points in an AI workflow, rather than allowing the AI to operate fully autonomously.
In plain English: Keeping a human involved in important decisions — the AI does the work but a person reviews or approves before anything critical happens.
In-Context Learning
LLMs & ModelsThe ability of a large language model to learn from examples provided within the prompt itself, without any weight updates or fine-tuning.
In plain English: Teaching an AI on the fly by including examples in your message. The AI adapts to your examples without any formal retraining.
Inference
TechnicalThe process of running a trained AI model to generate outputs from new inputs — as opposed to training, which is the process of teaching the model. When you use ChatGPT, you are performing inference.
In plain English: Using an AI model after it's been trained. Training is like going to school; inference is like using what you learned at work.
Jailbreak
Ethics & SafetyA prompt or technique designed to bypass an AI model's safety guardrails and get it to produce content it was trained to refuse.
In plain English: Tricking an AI into ignoring its rules — like finding a loophole in a company's content policy.
Large Language Model (LLM)
LLMs & ModelsA type of AI model trained on vast amounts of text data to understand and generate human language. LLMs are the technology behind ChatGPT, Claude, Gemini, and most modern AI writing tools.
In plain English: The AI brain behind most modern chatbots and writing tools. It's been trained on enormous amounts of text and can write, summarise, translate, and reason about almost any topic.
Latency
TechnicalThe time delay between sending a request to an AI model and receiving the first token of its response. Low latency is critical for real-time applications.
In plain English: How long you wait before the AI starts responding. High latency means a noticeable pause; low latency means near-instant replies.
Llama
LLMs & ModelsMeta's family of open-source large language models. Unlike GPT or Claude, Llama models can be downloaded and run locally on your own hardware, making them popular for privacy-conscious users and developers.
In plain English: Meta's AI models that you can download and run on your own computer — no internet connection or subscription required.
Machine Learning (ML)
Core AIA branch of AI in which systems learn from data to improve their performance on tasks without being explicitly programmed for each specific scenario.
In plain English: Teaching computers to learn from examples rather than writing rules for every situation. Show it 10,000 pictures of cats and it learns to recognise cats.
Midjourney
AI ToolsAn AI image generation tool that creates photorealistic and artistic images from text prompts. Known for its high aesthetic quality and active Discord community.
In plain English: Type a description and Midjourney draws it for you — from photorealistic portraits to fantastical landscapes.
Model
Core AIIn AI, a model is a mathematical system trained on data to make predictions or generate outputs. It encodes learned patterns as numerical parameters (weights).
In plain English: The AI itself — the trained system that takes your input and produces an output. When people say 'the model', they mean the AI's brain.
Multimodal AI
Core AIAI systems that can process and generate multiple types of data — such as text, images, audio, and video — within a single model.
In plain English: AI that can see, hear, and read — not just process text. You can show it a photo and ask questions about it, or give it audio and ask for a transcript.
Example: GPT-4o can take a photo of a maths problem and solve it, or listen to audio and respond in kind.
Natural Language Processing (NLP)
Core AIThe field of AI focused on enabling computers to understand, interpret, and generate human language in a useful way.
In plain English: The technology that lets computers understand what you're saying or writing — the foundation of every chatbot, translator, and voice assistant.
Neural Network
TechnicalA computational model loosely inspired by the human brain, consisting of layers of interconnected nodes (neurons) that process and transform data to learn patterns.
In plain English: A system of virtual 'neurons' arranged in layers that learn to recognise patterns — the building block of all modern deep learning AI.
Open Source AI
AI ToolsAI models whose weights, training code, or both are publicly released, allowing anyone to download, run, study, and modify them.
In plain English: AI you can download and use freely — no subscription, no API costs, and you can see exactly how it works.
OpenAI
AI ToolsThe AI research company behind ChatGPT, GPT-4, DALL-E, and Whisper. Founded in 2015, OpenAI is one of the most influential organisations in the AI industry.
In plain English: The company that made ChatGPT — currently the most widely used AI tool in the world.
Overfitting
TechnicalWhen an AI model learns the training data too well — including its noise and quirks — and performs poorly on new, unseen data as a result.
In plain English: When an AI memorises the answers to the practice test instead of actually learning the subject — it aces the practice but fails the real exam.
Parameters
TechnicalThe numerical values (weights and biases) inside a neural network that are adjusted during training. The number of parameters is a rough indicator of a model's capacity — GPT-4 is estimated to have over 1 trillion.
In plain English: The 'knobs' inside an AI that get adjusted during training. More parameters generally means a more capable model, but also more expensive to run.
Perplexity
AI ToolsAn AI-powered search engine that provides direct answers to questions with cited sources, combining the capabilities of a search engine with a language model.
In plain English: A smarter search engine — instead of giving you a list of links, it reads the web and gives you a direct answer with references.
Prompt
LLMs & ModelsThe input text or instruction given to an AI model to elicit a desired response. The quality and structure of a prompt significantly affects the quality of the output.
In plain English: What you type into an AI. A good prompt is clear, specific, and gives the AI enough context to give you a useful answer.
Example: Instead of 'write a blog post', a better prompt is 'Write a 600-word blog post for small business owners explaining how to use ChatGPT to save time on email.'
Prompt Engineering
CareersThe practice of designing, refining, and optimising prompts to reliably get high-quality, accurate, and useful outputs from AI language models.
In plain English: The skill of knowing how to talk to AI to get the best results. A good prompt engineer can get dramatically better outputs than someone using the same model with a vague prompt.
RAG (Retrieval-Augmented Generation)
TechnicalA technique that combines a language model with a retrieval system, allowing the AI to search an external knowledge base (like your documents or the web) before generating a response — reducing hallucinations and improving accuracy.
In plain English: Giving an AI access to a reference library so it can look things up before answering, rather than relying purely on what it memorised during training.
Example: A customer support chatbot using RAG can search your company's help documentation before answering, giving accurate, up-to-date responses.
Reasoning
LLMs & ModelsThe ability of an AI model to work through complex, multi-step problems logically — a capability that has improved dramatically with models like OpenAI's o1 and o3.
In plain English: AI that can think through hard problems step by step, rather than just pattern-matching to a quick answer.
Red Teaming
Ethics & SafetyA safety testing process where researchers deliberately try to find ways to make an AI model produce harmful, biased, or dangerous outputs — to identify and fix vulnerabilities before public release.
In plain English: Stress-testing an AI by trying to break it on purpose — finding the edge cases and failure modes before real users do.
RLHF (Reinforcement Learning from Human Feedback)
TechnicalA training technique where human raters evaluate AI outputs and their preferences are used to train a reward model, which then guides the AI to produce more helpful, harmless, and honest responses.
In plain English: Teaching an AI to be more helpful by having humans rate its answers and rewarding it for the ones people preferred — like training a dog with treats, but for language.
Stable Diffusion
AI ToolsAn open-source image generation model developed by Stability AI that can be run locally on consumer hardware. It is the basis for many third-party image generation tools and custom models.
In plain English: A free, open-source AI image generator you can run on your own computer — no subscription needed, and you can customise it extensively.
System Prompt
LLMs & ModelsA hidden instruction given to an AI model before the conversation begins, used to set its persona, tone, rules, and constraints. Users typically cannot see the system prompt.
In plain English: Secret instructions that tell the AI how to behave before you start chatting — like a briefing given to an employee before a customer call.
Temperature
TechnicalA parameter that controls the randomness of an AI model's outputs. A low temperature (near 0) produces more deterministic, predictable responses; a high temperature produces more varied and creative ones.
In plain English: A dial that controls how 'creative' or 'random' the AI is. Turn it down for factual, consistent answers; turn it up for more imaginative, varied responses.
Text-to-Image
AI ToolsAI systems that generate images from natural language descriptions (prompts). Examples include Midjourney, DALL-E, and Stable Diffusion.
In plain English: Type a description, get a picture. 'A photorealistic cat wearing a top hat in a Victorian library' becomes an actual image.
Token
TechnicalThe basic unit of text that language models process. A token is roughly 3–4 characters or about 0.75 words in English. Models have limits on how many tokens they can process at once (the context window).
In plain English: The chunks that AI breaks text into. 'Hello, world!' is about 4 tokens. AI pricing is usually based on how many tokens you use.
Example: 1,000 tokens ≈ 750 words. Most AI APIs charge per 1,000 tokens of input and output.
Training Data
Core AIThe dataset used to train an AI model. For large language models, this typically includes billions of web pages, books, and other text sources. The quality and composition of training data heavily influences model behaviour.
In plain English: The information an AI learned from. GPT-4 was trained on a huge portion of the internet and many books — that's why it knows so much.
Transfer Learning
TechnicalA technique where a model trained on one task is adapted for a different but related task, leveraging the knowledge it already acquired to learn more efficiently.
In plain English: Reusing what an AI already knows to learn something new faster — like a French speaker learning Spanish is much faster than someone starting from scratch.
Transformer
TechnicalThe neural network architecture introduced in the 2017 paper 'Attention Is All You Need' that became the foundation for virtually all modern large language models, including GPT, Claude, and Gemini.
In plain English: The architectural breakthrough that made modern AI possible. Almost every powerful AI model today is built on the Transformer design.
Vector Database
TechnicalA database optimised for storing and searching vector embeddings, enabling fast similarity search — a core component of RAG systems and semantic search applications.
In plain English: A special kind of database that stores information as numbers so an AI can quickly find the most relevant documents when answering a question.
Vision AI
Core AIAI systems that can analyse, interpret, and generate visual content — including image classification, object detection, OCR, and image generation.
In plain English: AI that can see. It can identify objects in photos, read text from images, describe scenes, and generate new images.
Whisper
AI ToolsOpenAI's open-source speech recognition model that can transcribe and translate audio in multiple languages with high accuracy.
In plain English: OpenAI's tool for turning speech into text — it can transcribe meetings, podcasts, and voice notes with impressive accuracy across many languages.
Zero-Shot Learning
LLMs & ModelsThe ability of an AI model to perform a task it was not explicitly trained for and has received no examples of, relying solely on its general knowledge and the task description.
In plain English: Asking an AI to do something without showing it any examples first — and it still does a reasonable job because of its broad training.
Example: Asking GPT-4 to classify customer sentiment in a language it was rarely trained on — it can often do it reasonably well without any examples.