Which to use
“fill” is a verb and “fly” is a noun - they look or sound alike but fill different roles in a sentence.
- #2,297
- “fill” frequency rank
- #1,827
- “fly” frequency rank
- 4124
- confusion score
Side-by-Side Comparison
| Feature | fill | fly |
|---|---|---|
| Definition | To make full | Any insect of the order Diptera; characterized by having two wings (except for some wingless species), also called true flies. |
Where the spellings diverge
Shared letters are muted; the letters that actually set fill and fly apart are highlighted. They share 2 letters in sequence, which is exactly why the eye skips the difference.
Spelling & Dictionary Insight
fill and fly 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 4124, derived from the frequency rank of both members and their visual similarity.
fill is recorded at frequency rank #2,297, classified as averb, pronounced /fɪl/. fly is at rank #1,827, tagged as anoun, pronounced /flaɪ/.
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 4124, this pair ranks #519,913 of 530,003 scored English confusable pairs - a relatively easy-to-tell-apart pair.
Frequency comparison
Frequently Asked Questions
Can "fill" and "fly" be used interchangeably?
Remembering fill vs fly
The fastest way to pick the right one every time.
- Check the role first: if you need a verb, it's “fill”; for a noun, it's “fly”.
- See each word in full, definition, IPA, etymology and its other confusables. Full “fill” entry
- Browse more pairs most likely to be confused. Most confusable