Main entry: engaged, in use, busy
Definition: (of facilities such as telephones or lavatories) unavailable for use by anyone else or indicating unavailability; (`engaged' is a British term for a busy telephone line)
Usage: her line is busy; receptionists' telephones are always engaged; the lavatory is in use; kept getting a busy signal
Main entry: in use
Definition: currently being used
Usage: robots are in use throughout industry