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PlainSpell

backup

/ˈbækˌʌp/noun, adjective

backup is spelled B-A-C-K-U-P: 6 letters and 2 syllables. It appears 16 times per million words in written English, the 5,025th most frequent word form (wordfreq, 2021 data). People search “back-up vs backup” about 170 times a month (Google, United States). As a noun, backup means “A reserve or substitute” (English Wiktionary, September 2026). The plural of backup is backups.

How many letters and syllables are in backup?

Letters6: B-A-C-K-U-P
Syllables2 (from its American pronunciation)
In writing16 times per million words; the 5,025th most frequent word form
Wrong spellings searchednone measured in search
Pairs people search

Sources: letters and syllables from the English Wiktionary's hyphenation or pronunciation and the CMU Pronouncing Dictionary; written frequency: wordfreq 3.1 (a 2021 snapshot of Wikipedia, subtitles, news, books, web text and social media); Bing searches in the United States: the average month from September 2025 to August 2026 (Microsoft Advertising keyword data through DataForSEO, read September 30, 2026).

How common is backup?

Backup appears 16 times per million words in written English, the 5,025th most frequent word form in the list.

Source: written frequency: wordfreq 3.1 (a 2021 snapshot of Wikipedia, subtitles, news, books, web text and social media).

How do you pronounce backup?

  • /ˈbækˌʌp/

Backup has 2 syllables (counted from its American pronunciation in the CMU Pronouncing Dictionary).

Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract). Recordings: LL-Q1860_(eng)-Vealhurl-backup.wav, Wikimedia Commons (author and licence on each file's page).

Words people confuse with backup

Word pairs people search, with the monthly searches for “a vs b” (G: Google, B: Bing, United States).

back-up vs backup170 G

Also written: back-up (one word or two).

Sources: Google and Bing searches (September 2025 to August 2026, through DataForSEO); English Wiktionary (homophones, alternative spellings).

Forms of backup

  • backups plural
  • back-up

Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract).

What does backup mean?

The meanings the English Wiktionary records, quoted as written there (source below).

noun

  1. 1

    A reserve or substitute.

    If the goalkeeper is injured, we have a backup.

  2. 2

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

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

  3. 3

    An accumulation of material caused by a (partial) obstruction or (complete) blockage of the flow or movement of the material, or an accumulation of material that causes an overflow due to the flow being greater than the maximum possible flow.

    The accident caused a mile-long backup on the highway.

  4. 4

    Reinforcements.

    He's got a gun! You'd better send for backup.

  5. 5

    Any support or extra help.

  6. 6

    Accompaniment.

  7. 7

    Corroboration.

adjective

  1. 1

    Standby, reserve or extra.

    I am only a backup player.

  2. 2

    That is intended as a backup.

    Make a backup copy of that file.

  3. 3

    Supporting, reinforcing; (music) of or related to accompaniment

Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract).

How do you abbreviate backup?

Wiktionary records one abbreviation of backup: B/U.

Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract).

Backup in Spanish, French, German and Portuguese

LanguageWords
Frenchremplaçant (reserve), sauvegarde (copy of file or record), de sauvegarde (intended as backup)
GermanUnterstützung, Deckung, Ersatz (reserve), Datensicherung, Backup, Reservekopie (copy of file or record)
Spanishrespaldo (reserve), copia de seguridad, copia de reserva/respaldo (copy of file or record), de reserva (standby, reserve or extra)
Portuguesebackup, becape, cópia de segurança, cópia de reserva (copy of file or record), reserva (standby, reserve or extra)

Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract). Translations are Wiktionary's, by sense; a linked word has its own PlainSpell page.

Where does backup come from?

Deverbal from back up.

Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract).

What to look up after backup