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 What about Kendall Lamm, the Browns’ backup tackle? Scott Patsko, cleveland, "With Joel Bitonio sidelined, what are the Browns’ options at left guard?," 5 Jan. 2021 But Roseman seemed to regard Hurts as a valuable backup when discussing the rookie QB on Monday. Mark Inabinett |, al, "When it’s sunny in Philadelphia, will Jalen Hurts be the quarterback?," 5 Jan. 2021 If Goff can’t go, the Rams will turn to backup John Wolford for the second consecutive game. oregonlive, "Los Angeles Rams’ Jared Goff faces ‘challenging’ road to play against the Seattle Seahawks in Wild Card playoff: Report," 5 Jan. 2021 Veteran Blake Bortles was Goff’s backup last season while Wolford ran the scout team against the first-team defense. Los Angeles Times, "How John Wolford’s long football journey prepared him for NFL opportunity," 2 Jan. 2021 Hoyer, now in his third stint in New England, began the season as Newton’s backup, started one game in which he got benched for Stidham, and has since been relegated to the inactive list each week. Nicole Yang,, "After first losing season in 20 years, big overhaul looming for Patriots," 31 Dec. 2020 Google offers 15 GBs of free storage for photos, but that also includes Gmail and Google Drive backup. Jefferson Graham, USA TODAY, "Are you willing to pay for email? How about podcasts? Here are our tech predictions for 2021," 30 Dec. 2020 But Medponics got some high-powered legal backup for its side. Sarah Freishtat,, "Illinois Supreme Court to decide fate of last contested medical marijuana growing license in the state," 30 Dec. 2020 As promising as that sounds, Michigan’s law sets a high bar for property owners seeking compensation after a sewage backup. Bill Laitner, Detroit Free Press, "Oakland cities settle sewage lawsuit for $11.5M, but homeowners will see little," 29 Dec. 2020 Recent Examples on the Web: Verb Even when the world opens back up, the movable, street-smart looks happening now are bound to stick. Erin Parker, Glamour, "15 Best Lug Sole Boots for Winter-Ready Edge," 6 Jan. 2021 But then, through a combination of restoration, sustainable practices, and aquaculture, the numbers began to climb back up, reaching 900,000 bushels in 2015. Melody Schreiber, The New Republic, "Can Oysters Save Our Seas?," 6 Jan. 2021 Trends appeared to improve in early December, although the positivity rate in Iowa has started to tick back up again in recent weeks. From Usa Today Network And Wire Reports, USA TODAY, "Hank Aaron, skeptic’s mea culpa, vaccine campouts: News from around our 50 states," 6 Jan. 2021 Ford was committed to the Owls for most of the year before opening his recruitment back up last week. Khobi Price,, "FAU Owls add 15 players, including four-star transfer linebacker to 2021 recruiting class," 16 Dec. 2020 With proper measures flying can be safer than eating at a restaurant during the pandemic, study says Nevada began reopening its economy May 1, with Las Vegas casinos opening back up the first week of June. Ian Duncan Washington Post, Star Tribune, "A woman died of coronavirus on a plane. Her fellow passengers were never notified.," 31 Oct. 2020 Even as Oregon cases soared, Gov. Kate Brown and Colt Gill, director of the Oregon Education Department, announced new metrics for opening schools back up. oregonlive, "Coronavirus cases in Oregon hits 600 for the first time," 30 Oct. 2020 Nevada began reopening its economy May 1, with Las Vegas casinos opening back up the first week of June. Washington Post, "A woman died of coronavirus on a plane. Her fellow passengers were never notified.," 30 Oct. 2020 Gyms are slowly opening back up across the country after many shuttered following the outbreak of Covid-19. Nicole Saunders, NBC News, "Best treadmills 2020: Trainers share their home treadmill choices," 27 Oct. 2020

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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Time Traveler for backup

Time Traveler

The first known use of backup was in 1801

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Statistics for backup

Last Updated

12 Jan 2021

Cite this Entry

“Backup.” Dictionary, Merriam-Webster, Accessed 18 Jan. 2021.

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More Definitions for backup


How to pronounce back up (audio)

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
US : 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

: a person who takes the place of or supports another The guard called for a backup.

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