Which to use
“flash” is a verb and “flask” is a noun - they look or sound alike but fill different roles in a sentence.
- #3,299
- “flash” frequency rank
- #22,379
- “flask” frequency rank
- 25678
- confusion score
Side-by-Side Comparison
| Feature | flash | flask |
|---|---|---|
| Definition | To cause to shine briefly or intermittently. | A narrow-necked vessel of metal or glass, used for various purposes; as of sheet metal, to carry gunpowder in; or of wrought iron, to contain quicksilver; or of glass, to heat water in, etc. |
Where the spellings diverge
Shared letters are muted; the letters that actually set flash and flask apart are highlighted. They share 4 letters in sequence, which is exactly why the eye skips the difference.
Spelling & Dictionary Insight
flash and flask 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 a single letter - h in “flash” becomes k in “flask” - close enough that the eye skips over the difference, far enough that meaning fully diverges. Our composite confusion score for this pair is 25678, derived from the frequency rank of both members and their visual similarity.
flash is recorded at frequency rank #3,299, classified as averb, pronounced /flæʃ/. flask is at rank #22,379, tagged as anoun, pronounced /ˈflɑːsk/.
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 25678, this pair ranks #392,475 of 530,003 scored English confusable pairs - roughly mid-pack for confusability.
Frequency comparison
Frequently Asked Questions
Can "flash" and "flask" be used interchangeably?
Remembering flash vs flask
The fastest way to pick the right one every time.
- Check the role first: if you need a verb, it's “flash”; for a noun, it's “flask”.
- See each word in full, definition, IPA, etymology and its other confusables. Full “flash” entry
- Browse more pairs most likely to be confused. Most confusable