Core Concepts
Foundation Model
Also known as: foundation models
In one line
A large, general-purpose model trained on broad data that can be adapted to many downstream tasks.
What does Foundation Model mean?
Foundation models (GPT-5, Claude, Gemini, Llama) are pretrained once at huge expense, then customised by prompting, RAG, or fine-tuning.
A real-world example
Anthropic's Claude is a foundation model; a customer-service bot built on top of it is an application.