A companion; a comrade.
One that habitually accompanies or is associated with another; an attendant circumstance.
A person united with another or others in an act, enterprise, or business; a partner.
One of a pair of elements of an integral domain (or a ring) such that the two elements are divisible by each other (or, equivalently, such that each one can be expressed as the product of the other with a unit).
Somebody with whom one works, coworker, colleague.
A member of an institution or society who is granted only partial status or privileges.