I'm not clear what they are called (or how implemented) — but perhaps 1) the initial prompt/context (that, for example, Grok has got in trouble with recently) and 2) the kind of saved context that allows ChatGPT to know things about your prompt-history so it can better answer future queries.
(My use of ollama has been pretty bare-bones and I have not seen anything covering these higher level features in -help.)