1. (adj)busy, engaged, in use(p) (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"
2. (adj)in use currently being used "robots are in use throughout industry"
Definition of 'in use'
