AI glossary
64 AI and prompting terms, each with a one-line plain-English version, a fuller definition, an example and a common mistake.
A
- AI agent
An AI system that can take actions toward a goal, such as searching, editing files or sending messages, not just answer questions.
- Alignment
The work of making AI systems pursue the goals and values their makers and users actually intend.
- Attention (in AI models)
The part of a transformer model that decides which other words matter most when processing each word.
C
- Chain-of-thought prompting
Asking the model to work through a problem step by step before giving its final answer.
- Context engineering
Deciding everything an AI model sees for a task: instructions, examples, documents, memory and tool results, not just the prompt wording.
- Context window
The maximum amount of text, measured in tokens, that an AI model can read and write in one go.
D
- Deep research
An AI mode that spends several minutes searching and reading many sources, then writes a detailed report with citations.
- Delimiters
Markers like triple quotes or XML tags that separate your instructions from the text you want the AI to work on.
- Diffusion model
A type of AI that generates images or video by starting from random noise and gradually refining it into a picture.
- Distillation
Training a smaller AI model to imitate a larger one, so you get similar results for less cost.
E
- Embeddings
Lists of numbers that represent the meaning of text, so a computer can find texts that mean similar things.
- Evals (AI evaluations)
Tests that measure how well an AI model or prompt performs on a set of example tasks.
F
- Few-shot prompting
Showing the model two or three examples of the task done well before asking it to do a new one.
- Fine-tuning
Training an existing AI model further on your own examples to change how it behaves.
- Foundation model
A large, general-purpose AI model trained on broad data that many different apps and tasks are built on top of.
G
- Generative AI
AI that creates new content, such as text, images, audio, code or video, rather than only sorting or predicting labels.
- Generative engine optimization (GEO)
Making your content easy for AI answer engines like ChatGPT search, Perplexity and Google AI Overviews to find, understand and cite.
- Grounding
Making an AI base its answer on specific sources you provide or it retrieves, instead of only its memory.
- Guardrails
Rules, checks and limits placed around an AI system to keep its behaviour safe and on task.
H
- Hallucination
When an AI model states something false or made up as if it were true.
I
- Inference
Running a trained AI model to get an answer. Every chat message you send triggers inference.
- Instruction tuning
Training that teaches a raw language model to follow instructions and answer like an assistant.
- Iterative prompting
Improving an AI result through a series of follow-up instructions, rather than expecting a perfect answer first time.
J
- Jailbreak
A prompt designed to trick an AI into ignoring its safety rules or usage policies.
K
- Knowledge cutoff
The date after which an AI model has no built-in knowledge, because its training data stops there.
L
- Large language model (LLM)
An AI model trained on huge amounts of text to predict and generate language, like the models behind ChatGPT and Claude.
- LLM-as-a-judge
Using an AI model to grade or compare AI outputs against criteria, instead of having people review every one.
- llms.txt
A plain-text file at a website’s root that tells AI tools what the site is about and which pages matter most.
M
- Max tokens
A setting that caps how long the AI’s reply can be, measured in tokens.
- MCP (Model Context Protocol)
An open standard that lets AI apps connect to tools and data sources, like a universal plug for AI integrations.
- Meta-prompting
Using an AI model to write, improve or critique prompts, rather than doing the task directly.
- Multimodal AI
AI that can work with more than one type of input or output, such as text, images, audio and video.
N
- Negative prompt
A list of things you do not want in an AI-generated image, such as blur, extra fingers or text.
O
- Open-weights model
An AI model whose trained parameters are published, so anyone can download and run it on their own hardware.
P
- Parameters
The internal numbers a model learns during training. Model size, like "70B", counts them in billions.
- Prefilling
Writing the first few words of the AI’s reply yourself, so it continues in the format you want.
- Prompt
The text you give an AI model to tell it what to do.
- Prompt caching
A feature that reuses the processed start of a prompt across requests, making repeated calls cheaper and faster.
- Prompt chaining
Splitting a big task into a sequence of smaller prompts, where each step uses the output of the last.
- Prompt engineering
Writing and testing instructions for an AI model so it reliably gives you the result you want.
- Prompt injection
An attack where hidden instructions in a document, email or web page trick an AI into doing something it should not.
- Prompt template
A reusable prompt with blanks, like {{AUDIENCE}}, that you fill in each time you use it.
Q
- Quantization
Storing an AI model’s numbers with less precision so it uses less memory and runs faster, with a small loss in quality.
R
- RAG (retrieval-augmented generation)
A setup where the AI first searches your documents for relevant passages, then answers using them.
- ReAct (reason and act)
A pattern where an AI alternates between thinking about what to do, taking an action with a tool, and checking the result.
- Reasoning model
An AI model trained to think through a problem at length before answering, which helps on hard maths, code and analysis.
- RLHF (reinforcement learning from human feedback)
A training method where people rate AI answers and the model learns to give answers that get better ratings.
- Role prompting
Telling the AI to act as a particular expert or character, such as an editor or a teacher.
S
- Self-consistency
Asking the same question several times, or several ways, and trusting the answer that comes up most often.
- Semantic search
Search that finds results by meaning, not just by matching the exact words you typed.
- Stop sequence
A piece of text that tells the AI to stop writing as soon as it produces it.
- Structured output
Getting an AI to answer in a fixed format, like JSON or a table, that software or people can use directly.
- Sycophancy
When an AI model tells you what you want to hear, agreeing or praising instead of being accurate or honest.
- System prompt
Standing instructions given to an AI model before the conversation starts, which shape every reply.
T
- Temperature
A setting that controls how random or predictable an AI model’s word choices are.
- Token
A small chunk of text, often part of a word, that AI models read and write. Usage and prices are counted in tokens.
- Tool use (function calling)
When an AI model asks to run a tool, like a search or a calculator, and uses the result in its answer.
- Top-p
A setting that limits the AI’s word choices to the most likely options that together add up to a set probability.
- Training data
The huge collection of text, code and other material an AI model learned from.
- Transformer
The neural network design behind almost all modern language models, built around a mechanism called attention.
- Tree of thoughts
A prompting approach where the model explores several possible paths, judges them, and continues with the most promising.
V
- Vector database
A database built to store embeddings and quickly find the ones most similar to a query.
- Vibe coding
Building software by describing what you want to an AI and accepting the code it writes, often without reading it closely.
Z
- Zero-shot prompting
Asking an AI model to do a task with instructions only, without showing it any examples.