an act of calling back.
a summoning of workers back to work after a layoff.
a summoning of an employee back to work after working hours, as for emergency business.
a request to a performer who has auditioned for a role, booking, or the like to return for another audition.
a return telephone call.
of or pertaining to such a call: Please leave a callback number.
1925–30; noun use of verb phrase call back