Synonyms of backup

1. backup, accretion, accumulation: usage: an accumulation caused by clogging or a stoppage; "a traffic backup on the main street"; "he discovered a backup in the toilet"
2. stand-in, substitute, relief, reliever, backup, backup man, fill-in, peer, equal, match, compeer: usage: 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"
3. accompaniment, musical accompaniment, backup, support, part, voice: usage: a musical part (vocal or instrumental) that supports or provides background for other musical parts
4. backup, computer backup, duplicate, duplication: usage: (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"
5. backing, backup, championship, patronage, blessing, approval, approving: usage: the act of providing approval and support; "his vigorous backing of the conservatives got him in trouble with progressives"