Princeton's WordNet

1. backup(noun)

   an accumulation caused by clogging or a stoppage

   "a traffic backup on the main street"; "he discovered a backup in the toilet"

2. stand-in, substitute, relief, reliever, backup, backup man, fill-in(noun)

   someone who takes the place of another (as when things get dangerous or difficult)

   "the star had a stand-in for dangerous scenes"; "we need extra employees for summer fill-ins"

3. accompaniment, musical accompaniment, backup, support(noun)

   a musical part (vocal or instrumental) that supports or provides background for other musical parts

4. backup, computer backup(noun)

   (computer science) a copy of a file or directory on a separate storage device

   "he made a backup in case the original was accidentally damaged or erased"

5. backing, backup, championship, patronage(noun)

   the act of providing approval and support

   "his vigorous backing of the conservatives got him in trouble with progressives"

Kernerman English Learner's Dictionary

1. backup(noun)ˈbækˌʌp

   additional help

   officers called for backup; a spare flashlight as a backup

2. backupˈbækˌʌp

   a copy of computer information

   a backup copy

Wiktionary

1. backup(Noun)

   A reserve or substitute.

   If the goalkeeper is injured, we have a backup.

2. backup(Noun)

   A copy of a file or record, stored separately from the original, that can be used to recover the original if it is destroyed or damaged.

   After the power failure, we had to restore the database from backup.

3. backup(Noun)

   An accumulation of material that halts the flow or movement of something.

   The blockage caused a backup in the plumbing.

4. backup(Noun)

   reinforcements

   He's got a gun - you better send for backup.

5. backup(Adjective)

   standby, reserve or extra

   I am only a backup player.

6. backup(Adjective)

   That is intended as a backup.

   Make a backup copy of that file.

• bystandAfrikaans
• قُوَّةُ دَعْـمArabic
• подкреплениеBulgarian
• reforçoPortuguese (BR)
• záloha, podporaCzech
• die VerstärkungGerman
• hjælpDanish
• ενισχύσεις, εφεδρικές δυνάμειςGreek
• refuerzoSpanish
• lisajõud, abivägiEstonian
• نیروی کمکیFarsi
• taustatukiFinnish
• renfortsFrench
• תִּגבּוֹרֶת, גִּבּוּיHebrew
• पीछे से समर्थनHindi
• potporaCroatian
• segítségHungarian
• bantuanIndonesian
• rinforzoItalian
• 支援（者）Japanese
• 후원자Korean
• pastiprinimas, paramaLithuanian
• papildspēkiLatvian
• bantuanMalay
• reserveDutch
• hjelp, oppbakking, reservemannskapNorwegian
• posiłkiPolish
• نیروی کمکیPersian
• مرستندوی قواPashto
• резерв; подкреплениеRussian
• posila, podporaSlovak
• pomočSlovenian
• pojačanjeSerbian
• förstärkning, uppbackningSwedish
• ผู้สนับสนุนThai
• yardım, destekTurkish
• 後備人員Chinese (Trad.)
• підтримка, резервUkrainian
• کمکUrdu
• lực lượng hỗ trợVietnamese
• 后援，后备者Chinese (Simp.)