1
as in to testify (to)
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1
as in jam
a crowded mass (as of cars) that impedes or blocks movement
there was the inevitable backup of travelers trying to pass through airport security
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2
as in replacement
a person or thing that takes the place of another
you didn't get the lead position, but you can be the backup to the chosen singer
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as in makeshift
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Examples of back (up) in a Sentence
Recent Examples on the Web
Kristine Thomason, Glamour, 3 Oct. 2024
Security guards received backup from Los Angeles Police Department officers sometime after 2 p.m., and a standoff ensued that lasted for about 90 minutes, according to local news reports.
—Chris Gardner, The Hollywood Reporter, 2 Oct. 2024
No injuries were reported, and the closure did not result in major traffic backups.
—Lorenzino Estrada, The Arizona Republic, 1 Oct. 2024
Neither Donald Trump nor Jimmy Kimmel seem able to stop talking about each other, but the late-night host is now calling for backup.
—Christian Holub, EW.com, 25 Sep. 2024
See all Example Sentences for back (up) 
Noun
Kristie Larson, a strength coach in New York City, swears by it for extra backup.
—Kristine Thomason, Glamour, 3 Oct. 2024
Security guards received backup from Los Angeles Police Department officers sometime after 2 p.m., and a standoff ensued that lasted for about 90 minutes, according to local news reports.
—Chris Gardner, The Hollywood Reporter, 2 Oct. 2024
No injuries were reported, and the closure did not result in major traffic backups.
—Lorenzino Estrada, The Arizona Republic, 1 Oct. 2024
Neither Donald Trump nor Jimmy Kimmel seem able to stop talking about each other, but the late-night host is now calling for backup.
—Christian Holub, EW.com, 25 Sep. 2024
See all Example Sentences for back (up)
These examples are programmatically compiled from various online sources to illustrate current usage of the word 'back (up).' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.
Thesaurus Entries Near back (up)
Cite this Entry
“Back (up).” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/back%20%28up%29. Accessed 21 Oct. 2024.
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