Flatmates is used in the UK for someone who you share a flat with but have separate rooms, and roommates is used where you share a room, but not a bed, or are not in a romantic relationship with. It's generally for places like student accommodation.

[–] where_am_i 3 points 1 month ago (1 children)

Yeah, but is it valid in American English to call someone a roommate even though each of you have a separate room?

[–] [email protected] 6 points 1 month ago (1 children)

American English yes, British English no.

I'm unsure about other English-speaking countries.

[–] [email protected] 1 points 1 month ago

My roommates got me a sweet car bed