Roommates are people who share or occupy the same living quarters. These people might share the same room, house or apartment.
Often college students have roommates when living in a dormitory. Commonly, roommates are friends or acquaintances. In other cases, a person might advertise to find a roommate that he or she does not know.
Roommate is chiefly an American term. It dates back to the late 1700s or early 1800s. The British term is "flatmate."
The term is obviously formed by the linking of "room" and "mate." The plural form is "roommates."
Friends, bedfellows and companions are some synonyms of roommate. Antonyms include enemy or foe.