Which to use
“lengthen” is a verb and “lengthy” is an adjective - they look or sound alike but fill different roles in a sentence.
- #36,640
- “lengthen” frequency rank
- #8,953
- “lengthy” frequency rank
- 45593
- confusion score
Side-by-Side Comparison
| Feature | lengthen | lengthy |
|---|---|---|
| Definition | To make longer, to extend the length of. | Having length; long and overextended, especially in time rather than dimension. |
Where the spellings diverge
Shared letters are muted; the letters that actually set lengthen and lengthy apart are highlighted. They share 6 letters in sequence, which is exactly why the eye skips the difference.
Spelling & Dictionary Insight
lengthen and lengthy 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 1 letter(s) in length - close enough that the eye skips over the difference, far enough that meaning fully diverges. Our composite confusion score for this pair is 45593, derived from the frequency rank of both members and their visual similarity.
lengthen is recorded at frequency rank #36,640, classified as averb, pronounced /ˈlɛŋθən/. lengthy is at rank #8,953, tagged as anadj.
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 45593, this pair ranks #219,793 of 530,003 scored English confusable pairs - roughly mid-pack for confusability.
Frequency comparison
Frequently Asked Questions
Can "lengthen" and "lengthy" be used interchangeably?
Remembering lengthen vs lengthy
The fastest way to pick the right one every time.
- Check the role first: if you need a verb, it's “lengthen”; for an adjective, it's “lengthy”.
- See each word in full, definition, IPA, etymology and its other confusables. Full “lengthen” entry
- Browse more pairs most likely to be confused. Most confusable