A working reference for AI terms you will see in product briefings, model cards, and technical conversations. Each entry starts plain, then explains what is actually happening under the hood.
AI designed to take a sequence of steps toward a goal, rather than only answer a single prompt.
What it actually is under the hood
An agent loops through a model, instructions, tools, and a working state. The model proposes the next action; software executes it and returns the result for another pass.
A defined way for software to ask another service for data or an action.
What it actually is under the hood
An API is usually an HTTP request with an authenticated key and structured input. Model APIs send text, files, or tool definitions and return structured model output.
The amount of text, code, or other input a model can consider in one request.
What it actually is under the hood
Inputs are converted to tokens and placed in the model's attention computation. A larger window raises compute and does not guarantee the model uses every detail equally well.
A numeric representation of text, images, or other data that captures useful similarity.
What it actually is under the hood
An encoder maps an item to a vector: a long list of numbers. Nearby vectors tend to represent related meanings, which makes similarity search practical.
Further training a base model on selected examples to make it better at a narrow job or style.
What it actually is under the hood
Training updates some or all of the model's weights using new examples. It can improve consistency, but it does not reliably add fresh factual knowledge.
A model output that sounds plausible but is inaccurate, unsupported, or invented.
What it actually is under the hood
A language model predicts likely next tokens; it does not check claims against reality by default. Retrieval, tools, and verification workflows reduce this risk but do not erase it.
The process of running a trained model to produce an answer, prediction, or generated file.
What it actually is under the hood
The model's fixed weights transform input tokens through many numerical operations. For language generation, this runs repeatedly, one token at a time.
An AI model trained to understand and generate language by predicting likely sequences of tokens.
What it actually is under the hood
An LLM is typically a transformer neural network trained on massive text collections. It turns words into tokens, computes relationships with attention, and predicts a probability distribution for the next token.
Designing instructions and examples so a model reliably produces useful output.
What it actually is under the hood
Prompts set the context the model uses to predict its next tokens. Clear constraints, examples, and structured outputs narrow the range of likely responses.
A method that gives a model relevant source material at answer time.
What it actually is under the hood
Software searches a document index, usually with embeddings and keyword matching, then places selected passages in the model's context window before generation.
A small unit of text a language model reads and generates; it may be a word, part of a word, or punctuation.
What it actually is under the hood
A tokenizer converts text into integer IDs from a fixed vocabulary. Model pricing, context limits, and output speed are usually measured in these units.
The neural-network architecture behind most modern large language models.
What it actually is under the hood
Its attention layers let each token weigh the relevance of other tokens in the input. Stacked layers build increasingly abstract representations before predicting output.