(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);
"her line is busy"
"receptionists' telephones are always engaged"
"the lavatory is in use"
"kept getting a busy signal"
currently being used;
"robots are in use throughout industry"
- Seriously damaged, the bridge is no longer in use.
- The audio device is in use at this time.
- The conference room is already in use.
- The new version of this dictionary is not in use yet.
- put in use 开始使用