add-on
"add-on" is a 5-letter English headword indexed on PlainSpell.
The verdict
“add-on” is outside the top-ranked English vocabulary, used as a noun - the kind of word writers most often double-check.
- Unranked
- below top-frequency English
- 6
- letters
According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - Something which can be appended to something else.
| Property | Value |
|---|---|
| Headword | add-on |
| Language | English |
| Part of speech | Noun |
| Letters | 6 |
| Misspellings tracked | 0 |
| Confusable pairs | 0 |
| Source | Wiktionary (kaikki.org) |
Where “add-on” sits in English frequency
Spelling & Dictionary Insight
The English entry for add-on is 6 letters long, classified as a noun. It sits outside the most-frequent rank tiers, which is often why uncommon words generate more spelling variants per reader. Wiktionary records 4 distinct senses for this headword, so context determines which meaning a reader should apply.
We couldn't generate a plausible misspelling set for add-on, and the word's spelling is regular enough that our generator found nothing worth flagging. This entry stands alone in our confusable dataset, since no other headword is close enough in sound or shape to pair with it.
Etymologically, the entry records: Deverbal from add on. The correct English form is add-on, spelled A-D-D---O-N.
Definition
- 1Something which can be appended to something else.
- 2A software extension or hardware peripheral that provides additional functions or customization for a core application or system.
- 3Additional chips that can be purchased at specific times in tournament play.
- 4Synonym of expansion pack.
Etymology
Deverbal from add on.
Synonyms
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.
Frequently Asked Questions
How do you spell "add-on"?
What does "add-on" mean?
What is the origin of the word "add-on"?
Is PlainSpell free to use?
Using “add-on”
The practical upshot for anyone who landed here from a spell-check.
- The one correct English spelling is A-D-D---O-N - every other letter order is a misspelling in standard orthography.
- Browse more English words and confusable pairs in the same reference. English words
Data Source
Wiktionary (via kaikki.org), licensed under CC BY-SA & GFDL. Word ordering uses an open word-frequency list; misspelling variants are generated by edit-distance from the correct headword.