backup

American  

[bak-uhp] / ˈbækˌʌp /

noun

1. a person or thing that supports or reinforces another.

2. a musician or singer or group of musicians or singers accompanying a soloist.

   a singer with a three-man backup that plays cello, bass, and guitar.

3. an overflow or accumulation due to stoppage, malfunctioning, etc..

   a sewage backup; a backup of cars at the tollbooth.

4. a person, plan, device, etc., kept in reserve to serve as a substitute, if needed.

5. Computers.

   1. a copy or duplicate version, especially of a file, program, or entire computer system, retained for use in the event that the original is in some way rendered unusable.

   2. a procedure to follow in such an event.

6. Bowling. a ball that curves in a direction corresponding to the bowling hand of the bowler.

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adjective

1. (of a person, plan, device, etc.) held in reserve as a substitute if needed.

   a backup driver; a backup generator.

2. performing a secondary or supporting function.

   A drummer and guitarist are the singer's backup musicians.

Usage

See login.

Etymology

Origin of backup

1775–85, noun use of verb phrase back up

Example Sentences

Although it appeared to acknowledge the server had been taken down, it said that was necessary for the backup to be restored.

From BBC • Apr. 3, 2026

The government would have to decide whether to use the fuel for backup power generators or for buses, tractors and trains needed to keep the economy going for two weeks, he added.

From Barron's • Mar. 30, 2026

Rivers, 27, has been a dependable backup and special teams contributor during his four seasons with the Rams.

From Los Angeles Times • Mar. 25, 2026

Not only does the Ellisons’ gamble look less sturdy, but so do their sources of backup.

From Slate • Mar. 20, 2026

They were my backup singers and moral support.

From "Breaking Through" by Francisco Jiménez

Related Words

• substitute