back up
"back-up" is a 6-letter English headword indexed on PlainSpell.
The verdict
“back up” is uncommon English (outside the top frequency list), classed as a verb. The kind of spelling people second-guess.
- Unranked
- below top-frequency English
- 7
- letters
According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - To move backwards, especially for a vehicle to do so.
Corpus desk
Index EN-back-up · back up · English
back up · unranked · 0 variants · 0 confusables
- FREQ-UNRANKED Unranked
- LEN-LONG 7 letters
- VOW-2 2 vowels
- CONFUS-0 No pairs
- VAR-0 0 variants
- BOOK-THIN "B" thin
- PHOTO-UNK Peer pending
Read with this headword: Spelling guide for this pattern
Desk codes from Wiktionary headword shape, FrequencyWords rank tier, confusable-pair count, generated misspelling depth, letter-cohort book size, and photo-finish peer. Not a difficulty grade.
| Property | Value |
|---|---|
| Headword | back up |
| Language | English |
| Part of speech | Verb |
| Letters | 7 |
| Misspellings tracked | 0 |
| Confusable pairs | 0 |
| Source | Wiktionary (kaikki.org) |
Long-tail rank of “back up” in English
Rare enough to double-check
back up is uncommon English outside the top frequency list, classed as averb. Rarity is why readers land here mid-draft. 12 senses are on record.
The misspelling generator found no plausible variants for back up, a straightforward case of a spelling with little room for common typos. It is not paired with a close-neighbour confusable in our dataset, since no other headword is close enough in sound or shape to pair with it.
No explicit etymology string is stored for this entry, so its spelling is best explained by sound-to-letter mapping rather than etymology. The correct English form is back up, spelled B-A-C-K- -U-P.
Definition
- 1To move backwards, especially for a vehicle to do so.
- 2To move a vehicle backwards.
- 3To undo one's actions.
- 4To reconsider one's thoughts.
- 5To copy (data) so that it can be restored if the main copy is lost.
- 6To provide support or the promise of support to.
- 7For the non-striker to take a few steps down the pitch, in preparation to taking a run, just as the bowler bowls the ball.
- 8For a fielder to position himself behind the wicket (relative to a team-mate who is throwing the ball at the wicket) so as to stop the ball, and prevent overthrows.
- 9To halt the flow or movement of something.
- 10To fill up because of a backlog.
- 11To run a printing press in reverse.
- 12If a property backs up to another property, that means it abuts or shares a border with another property.
Recorded use
Wiktionary examplesThese source excerpts show how back up appears in context. They illustrate usage; the definition above remains the entry’s reference meaning.
That beeping sound indicates that the truck is backing up.
We expressed our readiness, and in ten minutes were in the station wagon, rolling rapidly down the long drive, for it was then after nine.[…]As we reached the lodge we heard the whistle, and we backed up against one side of the platform as the train pulled up at the other.
This word in other languages
Definitions, pronunciation, and etymology for this entry are drawn from Wiktionary via the kaikki.org structured extract (CC BY-SA). See the methodology for how each field is sourced and updated.