Core Concepts
Foundation Model
A large pre-trained model that serves as the base for many downstream applications.
Foundation models are trained at massive scale on diverse data and designed to be adapted for many tasks via fine-tuning or prompting. The term emphasizes that these models form the foundation on which specialized AI systems are built. All major commercial LLMs — GPT-5, Claude, Gemini — are foundation models.
Related Terms
LLM
Large Language Model — a neural network trained on vast text corpora to generate human-like text.
Pre-Training
The initial large-scale training phase where a model learns language from massive text corpora.
Fine-Tuning
Continuing to train a pre-trained model on domain-specific data to adapt its behavior.
Instruction Tuning
Fine-tuning a model on examples of instructions paired with ideal responses.