[bak-uhp] 
| 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.
|
| 6. | Bowling. a ball that curves in a direction corresponding to the bowling hand of the bowler. |
| 7. | (of a person, plan, device, etc.) held in reserve as a substitute if needed: a backup driver; a backup generator. |
| 8. | performing a secondary or supporting function: A drummer and guitarist are the singer's backup musicians. |
| back·up (bāk'ŭp') n.
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