Back up or backup?
back up is a verb meaning “To move backwards, especially for a vehicle to do so”; backup is a noun meaning “A reserve or substitute”. Use back up as a verb and backup as a noun. back up is written as two words and backup as one word; they are used differently.
What is the difference between back up and backup?
| back up | backup | |
|---|---|---|
| Part of speech | verb, adjective, noun | noun, adjective |
| Meaning | To move backwards, especially for a vehicle to do so To move a vehicle backwards | A reserve or substitute 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 Standby, reserve or extra |
| Example | That beeping sound indicates that the truck is backing up | If the goalkeeper is injured, we have a backup |
| Forms | none | backups |
| Pronunciation | not recorded | /ˈbækˌʌp/ |
| In writing | not counted (the list counts single words) | 16 times per million words |
Sources: back up and backup in the English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0); written frequency: wordfreq 3.1 (a 2021 snapshot of Wikipedia, subtitles, news, books, web text and social media).
Every current meaning of back up and backup
back up
- 1
To move backwards, especially for a vehicle to do so
That beeping sound indicates that the truck is backing up
- 2
Alternative form of backup
- 3
Alternative form of backup
- 4
To move a vehicle backwards
Back up the car a little, you're blocking the driveway
- 5
To undo one's actions
I couldn't see how to finish the project, so I backed up and tried it another way
- 6
To reconsider one's thoughts
This isn't working. Let's back up and think about it
- 7
To copy (data) so that it can be restored if the main copy is lost
Back up your documents folder before applying the update
- 8
To provide support or the promise of support to
You should be careful. This guy is backed up by the local gang
backup
- 1
A reserve or substitute
If the goalkeeper is injured, we have a backup
- 2
Standby, reserve or extra
I am only a backup player
- 3
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
- 4
That is intended as a backup
Make a backup copy of that file
- 5
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…
The accident caused a mile-long backup on the highway
- 6
Supporting, reinforcing; (music) of or related to accompaniment
- 7
Reinforcements
He's got a gun! You'd better send for backup
- 8
Any support or extra help
Source: the English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0); obsolete, archaic, dialect and rare senses left out.
Which is more common, back up or backup?
back up is a phrase, which the list of single words does not count; backup 16 times per million words.
Source: written frequency: wordfreq 3.1 (a 2021 snapshot of Wikipedia, subtitles, news, books, web text and social media).
How many people search back up vs backup?
“back up vs backup” is searched about 170 times a month on Google and 30 on Bing in the United States. Google counts close variants of a query together (“backup vs back up”, “back up or backup”).
Sources: Google Ads keyword data through DataForSEO and Microsoft Advertising keyword data through DataForSEO, the average month from September 2025 to August 2026.