noun, often attributive
back·​up | \ ˈbak-ˌəp How to pronounce backup (audio) \

Definition of backup

 (Entry 1 of 2)

1a : one that serves as a substitute or support I brought an extra pencil for backup. a backup plan
b : musical accompaniment The tunes include banjo and guitar backup.
c : additional personnel who provide assistance The police officer called for backup.
2 : an accumulation caused by a stoppage in the flow traffic backup
3 : a copy of computer data (such as a file or the contents of a hard drive) I made a backup copy of the file. also : the act or an instance of making a backup

back up

backed up; backing up; backing up

Definition of back up (Entry 2 of 2)

intransitive verb

: to accumulate in a congested state traffic backed up for miles

transitive verb

1 : to move into a position behind (a teammate) in order to assist on a play
3 : to make a copy of (a computer file or data) to protect against accidental loss or corruption Be sure to back up your work. also : to make copies of all the files on (a device) a program that automatically backs up your hard drive

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Synonyms for backup

Synonyms: Noun

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Examples of backup in a Sentence

Noun His role on the team is to be a backup to the regular quarterback. We have an extra radio as a backup in case this one doesn't work. We have an extra radio for backup. He provides backup for the regular quarterback. She sang backup on his CD.
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Recent Examples on the Web: Noun Steed, who was previously backing up Smith, is expected to start alongside middle linebacker Corey Flagg Jr., with third-year redshirt freshman Avery Huff listed as Steed’s backup against the Spartans. Khobi Price,, 14 Sep. 2021 Implement backup and maintenance with access control. Evgeniy Altynpara, Forbes, 7 Sep. 2021 Officers followed the truck, called in San Diego police as backup and stopped the truck. David Hernandez, San Diego Union-Tribune, 26 Aug. 2021 Rising, who won the job last fall, but is coming off major surgery to his throwing shoulder, will be Brewer’s backup. Josh Newman, The Salt Lake Tribune, 26 Aug. 2021 Shaw, who started all seven games last season, is not listed on the two-deep, with freshman Devin Kirkwood listed as Johnson’s backup. Houston Mitchell Assistant Sports Editor, Los Angeles Times, 24 Aug. 2021 Further, King served actively as Mond’s backup in 2020 after Calzada had the year prior. Dallas News, 13 Aug. 2021 At this time last year, Cincinnati Bengals backup quarterback Brandon Allen was competing for a spot on the team’s roster. Charlie Goldsmith, The Enquirer, 11 Aug. 2021 But the Browns botched the paperwork, missed the deadline and McCarron stayed in Cincinnati as Andy Dalton’s backup. Mark Inabinett |, al, 12 July 2021 Recent Examples on the Web: Verb One difference from last season — Marlon Mack will back up last season’s top rookie rusher, Jonathan Taylor, who averaged 5.9 yards and scored eight touchdowns in his final seven games but didn’t play in the preseason. Mark Heim |, al, 12 Sep. 2021 Hoyer will back up rookie Mac Jones, who will make his NFL debut., 11 Sep. 2021 WhatsApp users can back up their data and store it on clouds that don’t belong to Facebook. Chris Smith, BGR, 10 Sep. 2021 Lone Star can back up its early claim as the best team in Frisco with a strong showing over Aledo, one of the best programs in the state and reigning 5A-II champions. Greg Riddle, Dallas News, 29 Aug. 2021 The video does not back up the claims in the Facebook post. Daniel Funke, USA TODAY, 27 Aug. 2021 Case Keenum showed why Cleveland invested in him to back up Baker Mayfield, throwing a touchdown pass and leading the Browns to a 17-13 win over the New York Giants in an exhibition game Sunday. Tom Withers, ajc, 22 Aug. 2021 Your containers also need to have drainage holes in the bottom, or water can back up in the pots and cause your plants to stop growing with off-color foliage. Tim Johnson,, 21 Aug. 2021 But the danger remained that Mr. Saied would back up his power grab with greater force, whether by further deploying the military or arresting top officials. New York Times, 5 Aug. 2021

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'backup.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of backup


1910, in the meaning defined at sense 1a


1801, in the meaning defined at intransitive sense

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Dictionary Entries Near backup

back up


backup light

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Statistics for backup

Last Updated

21 Sep 2021

Cite this Entry

“Backup.” Dictionary, Merriam-Webster, Accessed 22 Sep. 2021.

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More Definitions for backup



English Language Learners Definition of backup

: a person or thing that can be used to replace or support another person or thing
: help or support provided by additional people or things
: a situation in which the flow of something (such as traffic) becomes blocked


back·​up | \ ˈbak-ˌəp How to pronounce backup (audio) \

Kids Definition of backup

1 : a person who takes the place of or supports another The guard called for a backup.
2 : a situation in which the flow of something becomes blocked
3 : a copy of information stored on a computer

More from Merriam-Webster on backup

Nglish: Translation of backup for Spanish Speakers

Britannica English: Translation of backup for Arabic Speakers


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