AI glossary

The words that come up every time people talk about AI, explained plainly and with an example. Start with token and LLM: with those two, almost everything else makes sense.

AI agent
An AI agent is a system where a model does more than answer: it decides on steps, uses tools and acts in a loop until it reaches a goal.
Artificial intelligence (AI)
Artificial intelligence is the field that gets computers to do tasks we associate with human intelligence: understanding language, seeing, deciding or creating.
Context window
The context window is the maximum number of tokens a model can take into account at once: your message, the conversation, any documents and its own answer.
Embeddings
An embedding is a list of numbers that represents the meaning of a text or an image. Texts with similar meaning end up close to each other.
Fine-tuning
Fine-tuning means further training an already trained model on a small set of your own examples, to specialize it in a task, a style or a format.
Generative AI
Generative AI is AI that creates new content (text, images, audio, video or code) based on what it learned from huge numbers of examples.
Hallucination
A hallucination is when an AI model generates false or made-up information and presents it with full confidence, as if it were a real fact.
LLM (large language model)
An LLM (large language model) is an AI model trained on huge amounts of text to predict the next token. It is the engine behind ChatGPT, Claude and Gemini.
Machine learning
Machine learning is the branch of AI where a system learns patterns from examples instead of following rules someone programmed by hand.
MCP (Model Context Protocol)
MCP is an open protocol for connecting AI models to external tools and data, so that a single integration works across many applications.
Neural network
A neural network is a model made of layers of simple connected units, with weights that are adjusted during training. It is the basis of deep learning and of LLMs.
Prompt
A prompt is the instruction or text you give an AI model so it responds. The clearer the context and the goal, the better the answer tends to be.
RAG (retrieval-augmented generation)
RAG is a technique that finds relevant information in your documents and hands it to the model along with the question, so it answers with real, current data.
Temperature
Temperature is a setting that controls how much randomness a model uses when picking the next token: low gives more predictable answers, high gives more varied ones.
Token
A token is the small chunk of text a language model works with: a word, part of a word or a symbol. Context length and cost are both measured in tokens.
Transformer
The transformer is the neural network architecture behind almost every current LLM. Its key piece, attention, relates each token to all the others.

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