Definitions
1.nounA friend; a pal."I ran into an old chum from school the other day."
2.nounA roommate, especially in a college or university.
3.verbTo share rooms with someone; to live together.
4.verbTo lodge (somebody) with another person or people.
5.verbTo make friends; to socialize.
6.verbTo accompany."I'll chum you down to the shops."