roomie
noun (North American English, informal)(also room-mate British English, roommate North American English)
a person that you share a room with, especially at a college or university （尤指大学里的）室友，同住一室的人 - (North American English) (British English flatmate)
a person who shares a flat with one or more others 合住公寓套间者；同住一屋的人