Roomie (noun)

1. A person with whom one shares a room, typically a dorm room or apartment.
2. A roommate or someone who lives with another person in a shared living space.

Origin:

Slang shortening of "room-mate".

Examples:

1. She and her roomie were great friends.
2. He and his roomie had been living together for two years.
3. She was worried about getting a good roomie in college.
4. He and his roomie had a great time living together.
5. She and her roomie were able to split the costs of the apartment.