backup
noun.
an accumulation caused by clogging or a stoppage
a traffic backup on the main street|he discovered a backup in the toilet
noun.
someone who takes the place of another (as when things get dangerous or difficult)
the star had a stand-in for dangerous scenes|we need extra employees for summer fill-ins
noun.
a musical part (vocal or instrumental) that supports or provides background for other musical parts
noun.
(computer science) a copy of a file or directory on a separate storage device
he made a backup in case the original was accidentally damaged or erased
noun.
the act of providing approval and support
his vigorous backing of the conservatives got him in trouble with progressives