callback

noun

1. an act of calling back.
2. a summoning of workers back to work after a layoff.
3. a summoning of an employee back to work after working hours, as for emergency business.
4. a request to a performer who has auditioned for a role, booking, or the like to return for another audition.
5. recall(def 12).
6. a return telephone call.

adjective

7. of or relating to such a call: Please leave a callback number.