- a person or thing that supports or reinforces another.
- 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.
- an overflow or accumulation due to stoppage, malfunctioning, etc.: a sewage backup; a backup of cars at the tollbooth.
- a person, plan, device, etc., kept in reserve to serve as a substitute, if needed.
- Computers.
- 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.
- a procedure to follow in such an event.
- a ball that curves in a direction corresponding to the bowling hand of the bowler.
- (of a person, plan, device, etc.) held in reserve as a substitute if needed: a backup driver; a backup generator.
- performing a secondary or supporting function: A drummer and guitarist are the singer's backup musicians.
- to support or assist
- (of a nonstriking batsman) to move down the wicket in readiness for a run as a ball is bowled
- (of water) to accumulate
- (of traffic) to become jammed behind an accident or other obstruction
- to make a copy of (a data file), esp for storage in another place as a security copy
- to print the second side of (a sheet)
- to repeat an action immediately
- a support or reinforcement
- a reserve or substitute
- (as modifier)
- US and Canadian
- musical accompaniment, esp for a pop singer
- (as modifier)
- the overflow from a blocked drain or pipe
- a file or set of files copied for security purposes
