a sitting room in schools, colleges, etc, for the relaxation of students or staff
WordReference Random House Unabridged Dictionary of American English © 2025
com′mon room′,
- a room or lounge for informal use by all.
- 1660–70
Collins Concise English Dictionary © HarperCollins Publishers::
'common room' also found in these entries (note: many are not synonyms or translations):