n.
Pronunciation: - ˌ ə p
Function: noun
Usage: often attrib
Date: 1951
1 a : one that serves as a substitute or support <a backup plan> b : musical accompaniment c : additional personnel who provide assistance
2 : an accumulation caused by a stoppage in the flow <traffic backup >
3 : a copy of computer data (as a file or the contents of a hard drive) also : the act or an instance of making a backup