Backup

How to spell backup

6 letters · 2 syllables

How to pronounce backup

Say the part in capitals loudest.

What does backup mean?

1. nounA spare copy of files or data kept in case the original is damaged or lost.
2. nounA person or thing held in reserve to provide help or support if needed.
3. adjectiveKept ready as a spare or substitute for the main one.

Backup in a sentence

• noun

  She restored the lost report from last night's backup.

• noun

  The officer called for backup before approaching the building.

• adjective

  The hospital switched to its backup generator during the storm.

• noun

  The company keeps a backup of every customer record on a separate server.

• noun

  We hired a second driver as a backup for the long route.

• adjective

  Keep a backup plan in case the flight is cancelled.

Where does backup come from?

Language of origin: Germanic

This is a thoroughly Germanic compound built from two of the oldest words in English. 'Back' descends from the Old English 'baec', meaning the rear part of the body or anything behind, while 'up' comes from Old English 'upp', meaning toward a higher position. As a two-word phrasal verb, 'to back up' meant literally to move backward or to support someone from behind, and that sense of standing behind or reinforcing is the key to its modern meaning. The single fused noun 'backup' is much younger, emerging in American usage in the twentieth century to mean a reserve or reinforcement. With the rise of computing from the 1950s onward it took on its now dominant sense: a spare copy of data kept safe in case the original is lost. The spelling trap is simply remembering that the noun and adjective are written as one solid word, whereas the verb 'to back up' stays as two.

How the word is built

• back (rear, behind)
• up (adverb/particle), fused into a closed compound noun