back up

British  

verb

1. (tr) to support or assist

2. (intr) cricket (of a nonstriking batsman) to move down the wicket in readiness for a run as a ball is bowled

3. (of water) to accumulate

4. (of traffic) to become jammed behind an accident or other obstruction

5. computing to make a copy of (a data file), esp for storage in another place as a security copy

6. printing to print the second side of (a sheet)

7. to repeat an action immediately

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noun

1. a support or reinforcement

2. 1. a reserve or substitute

   2. ( as modifier )

      backup troops

3. 1. musical accompaniment, esp for a pop singer

   2. ( as modifier )

      backup singer

4. the overflow from a blocked drain or pipe

5. computing a file or set of files copied for security purposes

back up Idioms  

1. Move or drive a vehicle backward, as in He told her to back up into the garage . [First half of 1800s]

2. Bring or come to a standstill, as in The water had backed up in the drains , or The accident had backed up traffic for miles . [First half of 1800s]

3. Support or strengthen, as in The photos were backed up with heavy cardboard so they couldn't be bent , or I'll back up that statement of yours . [Second half of 1700s]

4. Duplicate a file or program so that the original is not lost. For example, Every computer manual warns you to back up your work frequently in case of a power outage or computer failure . [Second half of 1900s]

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Example Sentences

See Examples For:

back up

Then I noticed a footprint that I didn’t make, at least not directly, had crept back up onto Page 1 of the search results.

From Slate ● Aug. 6, 2026

Gulf allies have asked the U.S. in recent weeks for more air-defense interceptors and continued guarantees that the U.S. military will protect them if the tit-for-tat fighting flares back up, officials have said.

From The Wall Street Journal ● Aug. 5, 2026

"Manufacturing's share of GDP has gone down from 17% in 2015 to 14% currently. And manufacturing employment fell for five years after 2015 and has only now climbed back up slightly above those levels."

From BBC ● Aug. 3, 2026

With this much time off, however, Ohtani will need to build back up to a starter’s workload without the benefit of a rehab assignment, similar to what he did last season.

From Los Angeles Times ● Aug. 3, 2026

All the Mountain Dew he’d drunk came back up, along with the—never mind, Jonah told himself.

From "Found" by Margaret Peterson Haddix

Related Words

• fall back
• retreat