Model
The trained system you interact with. Under the hood it is a very large mathematical function, but people usually mean the whole thing they chat with.
Like a recipe distilled from watching many cooks. The original examples are gone, but the pattern remains.
Parameters or Weights
The numbers inside a model. Together they encode the patterns learned during training. More parameters can mean more capability, but also more compute.
Like billions of tiny dial positions inside a machine.
Training
The expensive process of building a model by feeding it huge amounts of data, checking predictions, and adjusting the weights again and again.
Inference
Running a trained model to get an answer. Every prompt you send to a hosted AI service triggers inference.
LLM
A large language model. It predicts and generates text-like sequences, which is why it can write prose, code, plans, summaries, and structured data.