Definition of callbacks:
(n) :
(programming) A function pointer passed as an argument to another function.
(n) :
(telephony) A return telephone or radio call; especially one made automatically to authenticate a logon to a computer network.
(n) :
(theater) A follow-up audition in casting.
(n) :
(business) A follow-up interview in employment recruiting.
(n) :
(comedy) A joke which references an earlier joke in the same routine.
(n) :
The return of a situation to a previous position or state; a reference to such a position or state.