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1. An accumulation caused by clogging or a stoppage
   "a traffic backup on the main street"; "he discovered a backup in the toilet"
    
2. Someone who takes the place of another (as when things get dangerous or difficult)
   - stand-in, substitute, relief, reliever, backup man, fill-in
    
3. A musical part (vocal or instrumental) that supports or provides background for other musical parts
   - accompaniment, musical accompaniment, support
    
4. (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"
   - computer backup
    
5. The act of providing approval and support
   - backing, championship, patronage

1. Give moral or psychological support, aid, or courage to
   - support
    
2. Move backwards from a certain position
   - back off, back down
    
3. Establish as valid or genuine
   "Can you back up your claims?"
   - back
    
4. Make a copy of (a computer file) especially for storage in another place as a security copy
   "You'd better back up these files!"
    
5. Become or cause to become obstructed
   "The water pipe is backed up"
   - clog, choke off, clog up, congest, choke, foul

Derived forms: backs up, backed up, backing up, backups

See also: back

Type of: accretion, accumulation, affirm, approval, approving, blessing, block, close up, compeer, confirm, copy, corroborate, draw back, duplicate, duplication, equal, impede, jam, match, move back, obstruct, obturate, occlude, part, peer, pull away, pull back, recede, re-create, retire, retreat, substantiate, support, sustain, voice, withdraw

Encyclopedia: Back up