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

However, these solutions also require interconnection and backup transmission capacity.

From MarketWatch • Apr. 8, 2026

The phenomenon is "something that we have not witnessed often," the mission's backup astronaut Jenni Gibbons told AFP.

From Barron's • Apr. 8, 2026

Over his two seasons as a backup, he scored just five points a game.

From The Wall Street Journal • Apr. 7, 2026

"The wastewater tank is not full and the toilet is operational; however, the crew was instructed to use backup collection devices overnight if needed," Nasa said.

From BBC • Apr. 5, 2026

“Don’t worry. Things aren’t that bad. And your father and I always have a backup plan. Just in case.”

From "The Parker Inheritance" by Varian Johnson

Related Words

• substitute