At Oxford and Cambridge Universities: a room in a college to which fellows have access for work and relaxation; = common room, n. 2a. Obsolete.

The name given in the university of Cambridge (England) to the college parlour where the fellows meet after dinner, elsewhere called common room, n.

A shared room in a college, school, etc., typically used for rest or relaxation, to which a certain category of people are allowed access.

Of institutions, associations, etc. reserved for the senior members of a body, as senior common-room, senior mess, etc.

Junior Common Room.

a common room in a college used by graduate students; graduate students collectively; abbreviated M.C.R.

A room or other area of a building intended for shared use; spec. an area in a shared residential facility for the use of all residents or visitors…