backup

1 of 2

noun

back·​up ˈbak-ˌəp How to pronounce backup (audio)
often attributive
1
a
: 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

2 of 2

verb

backed up; backing up; backing up

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
2
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

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.
Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Noun
Despite her best efforts to win them over, Meredith's well-meaning yet unseemly attempts only widen the gap, leading her to summon her sister (Claire Danes) for backup. Skyler Caruso, People.com, 19 Dec. 2024 In his final season, the dual-threat quarterback went from backup to All-Mountain West selection, passing for 1,845 yards and 17 touchdowns to just five interceptions while rushing for 824 yards and nine touchdowns. Anthony De Leon, Los Angeles Times, 18 Dec. 2024
Verb
There's a sweet spot for the perfect cuppa, where the rate of flow is sufficiently slow to absorb most of the flavor from the beans, but also fast enough not to back up in the filter. Ars Technica, 30 Dec. 2024 While fewer than one-fifth (18.1%) of all U.S. TV homes access OTA programming via an antenna, the big uptick in network coverage is almost certain to help bring the numbers back up, as the direct impact of the shrinking pay-TV universe is reduced. Anthony Crupi, Sportico.com, 27 Dec. 2024 See all Example Sentences for backup 

Word History

First Known Use

Noun

1910, in the meaning defined at sense 1a

Verb

1801, in the meaning defined at intransitive sense

Time Traveler
The first known use of backup was in 1801

Dictionary Entries Near backup

Cite this Entry

“Backup.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/backup. Accessed 3 Jan. 2025.

Kids Definition

backup

1 of 2 noun
back·​up ˈbak-ˌəp How to pronounce backup (audio)
1
: a person or thing that takes the place of or supports another
has a backup in case he gets sick
2
: a gathering or piling up because the flow has been stopped
a traffic backup
3
: a copy of a computer file to protect against loss of data
also : the act or an instance of making a backup

back up

2 of 2 verb
1
: to gather or pile up because the flow has been stopped
traffic backed up for miles
2
: to make a copy of (as a computer file) to protect against loss of data

More from Merriam-Webster on backup

Last Updated: - Updated example sentences
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!