Core Concepts
Large Language Model (LLM)
Also known as: large language model
In one line
A neural network trained on huge text collections to predict the next word — the engine behind ChatGPT, Claude and Gemini.
What does Large Language Model (LLM) mean?
A Large Language Model (LLM) is a machine-learning model with billions of parameters trained on internet-scale text. It learns patterns of language deeply enough to write, summarise, translate, code, and reason at near-human quality on many tasks.
A real-world example
GPT-5, Claude 4.5 Sonnet, and Gemini 2.5 Pro are all LLMs.
Related terms
Token
The unit of text an AI reads and generates — roughly ¾ of a word.
Context Window
The maximum amount of text an AI can hold in mind at once.
Transformer
The neural network architecture behind almost every modern LLM.
Foundation Model
A large, general-purpose model trained on broad data that can be adapted to many downstream tasks.