backup

American  

[bak-uhp] / ˈbækˌʌp /

noun

backups plural

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.

Other Word Forms

Noun Inflected Forms

• backups
  plural

Etymology

Origin of backup

1775–85, noun use of verb phrase back up

Explanation

Backup is what someone gives when they help or support you. A brand new doctor might need some backup in the emergency room for the first few weeks. Use the noun backup when you talk about extra assistance or help. Police officers call for backup when they're not sure they can handle a situation on their own, and store cashiers need backup when things get busy and customers start lining up. Another kind of backup is the one you do on your computer — in this case, a backup is the process of copying your data in case you lose the original files.

Example Sentences

The Lakers got their backup big man when Kevon Looney signed a one-year, $3.9-million deal on Tuesday, people not authorized to speak publicly told The Times.

From Los Angeles Times • Jul. 7, 2026

The company also offers employees access to services that can help them book backup care and navigate healthcare providers.

From MarketWatch • Jul. 7, 2026

Looney will be the backup behind starter Walker Kessler, who was acquired in a trade from the Utah Jazz and agreed to a four-year, $130-million deal.

From Los Angeles Times • Jul. 7, 2026

"Our energy workers have managed to reconnect power via backup schemes to almost all facilities, and electricity has been restored to most residential buildings in Sevastopol," Razvozhayev wrote on Telegram hours after the attack.

From Barron's • Jul. 6, 2026

That was why he had a backup plan in case his parents wouldn’t let him keep it.

From "Hello, Universe" by Erin Entrada Kelly

Related Words

• substitute