Ah, that's a good question actually. My above example has an error in it. If you have a segment called "ZEROPAGE" it will be automatically assumed by the assembler to be a zeropage segment.
Otherwise you have to manually do it:
If you forget, you get absolute addressing for everything. (Hopefully you'd catch this when getting an assembly error when trying to use a pointer, etc.)
Other than that, there's no special names for segments or memory blocks unless you want to use cc65 (it expects a bunch of specifically named segments by default, but they can all be changed). MEMORY regions can share the same names as SEGMENTS (i.e. they're different namespaces), but I always keep them unique, myself, for no particular reason.
See: ca65 docs: .segment
If you use .segment once with zeropage, it should generate an error if you ever forget to use zeropage anywhere else (this is checked globally by the linker), so there is a good amount of safety checks against doing it wrong. As long as you remember at least once, you're safe.
I tend to put all my allocations together in one file, so I forget about these rules; I don't have to think about them often.
Usually I just name the zeropage segment "ZEROPAGE" so I don't have to remember this rule.