Definition of "backup"

backup

/ˈbækˌʌp/

noun
plural backups
1. A reserve or substitute.
2. (computing) A copy of a file or record, stored separately from the original, that can be used to recover the original if it is destroyed or damaged.
3. An accumulation of material caused by a (partial) obstruction or (complete) blockage of the flow or movement of the material, or an accumulation of material that causes an overflow due to the flow being greater than the maximum possible flow.
4. (law enforcement) reinforcements
  Quotations
  Shaman: My patience is tested, but Uvenk invokes correctly. Grunt, who is your krantt? Your allies willing to kill and die on your behalf?Shepard: How is a candidate tested if he brings backup on his Rite of Passage?Shaman: Not every krogan can be the strongest warrior, but each must inspire his peers to battle at his side.Shaman: If the ones who know you best can find nothing worthy in you, you should wander the wastes and die alone before you weaken my clan.
  2010, BioWare, Mass Effect 2 (Science Fiction), Redwood City: Electronic Arts, PC, scene: Tuchanka
5. Any support or extra help.
6. (music) Accompaniment
  Quotations
  Debbie Ahn, on piano, provided some mesmerizing back-up and many fiery, on-target solos.
  1984 April 21, Pam Gordon, “'There's Always Cost': Ferron's Boston Concert”, in Gay Community News, page 17
adjective
not comparable
1. Standby, reserve or extra.
2. (computing) That is intended as a backup.
3. (music) of or related to accompaniment
verb
third-person singular simple present backups, present participle backupping, simple past and past participle backupped
1. (computing, nonstandard) Alternative form of back up
  Quotations
  We have two methods for backupping: the first one is writing the contents of disks onto magnetic tapes and the other is making a copy of the contents of disks on the disk of the mainframe computers of the laboratory.
  1989, CERN, page 235