What is a Context? Is it like a scope in C? Does it have a start and an end? Can contexts contain other contexts?
I see Contexts being used in lambda calculi type system rules, but I don't understand concretely what they are and why they are necessary. If they are too abstract, then is there some visual or metaphorical description?
Update: I am referring to "contexts" as what is to the left of ⊢ in typing calculi.