Which to use
“length” is a noun and “lengthen” is a verb - they look or sound alike but fill different roles in a sentence.
- #1,765
- “length” frequency rank
- #36,640
- “lengthen” frequency rank
- 38405
- confusion score
Side-by-Side Comparison
| Feature | length | lengthen |
|---|---|---|
| Definition | The distance measured along the longest dimension of an object. | To make longer, to extend the length of. |
Where the spellings diverge
Shared letters are muted; the letters that actually set length and lengthen apart are highlighted. They share 6 letters in sequence, which is exactly why the eye skips the difference.
Spelling & Dictionary Insight
length and lengthen form a confusable pair in the English index, two distinct headwords that are easily confused because they look alike, sound alike, or both. They differ by 2 extra letter(s) - “length” sits inside “lengthen” - close enough that the eye skips over the difference, far enough that meaning fully diverges. Our composite confusion score for this pair is 38405, derived from the frequency rank of both members and their visual similarity.
length is recorded at frequency rank #1,765, classified as anoun, pronounced /lɛŋ(k)θ/. lengthen is at rank #36,640, tagged as averb, pronounced /ˈlɛŋθən/.
Glosses for this pair are partially populated in our dataset, but the full side-by-side definitions above should still guide you to the right choice.
With a confusion score of 38405, this pair ranks #286,193 of 530,003 scored English confusable pairs - roughly mid-pack for confusability.
Frequency comparison
Frequently Asked Questions
Can "length" and "lengthen" be used interchangeably?
Remembering length vs lengthen
The fastest way to pick the right one every time.
- Check the role first: if you need a noun, it's “length”; for a verb, it's “lengthen”.
- See each word in full, definition, IPA, etymology and its other confusables. Full “length” entry
- Browse more pairs most likely to be confused. Most confusable