Which to use
“mast” is a noun and “must” is a verb - they look or sound alike but fill different roles in a sentence.
- #14,584
- “mast” frequency rank
- #198
- “must” frequency rank
- 14782
- confusion score
Side-by-Side Comparison
| Feature | mast | must |
|---|---|---|
| Definition | A tall, slim post or tower, usually tapering upward, used to support, for example, sails or observation platforms on a ship, the main rotor of a helicopter, flags, floodlights, meteorological instruments, or communications equipment, such as an aerial, usually supported by guy-wires (except in the case of a helicopter). | To do as a requirement; indicates that the sentence subject is required as an imperative or directive to execute the sentence predicate, with failure to do so resulting in a failure or negative consequence. |
Where the spellings diverge
Shared letters are muted; the letters that actually set mast and must apart are highlighted. They share 3 letters in sequence, which is exactly why the eye skips the difference.
Spelling & Dictionary Insight
mast and must 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 - a in “mast” becomes u in “must” - close enough that the eye skips over the difference, far enough that meaning fully diverges. Our composite confusion score for this pair is 14782, derived from the frequency rank of both members and their visual similarity.
mast is recorded at frequency rank #14,584, classified as anoun, pronounced /mɑːst/. must is at rank #198, tagged as averb, pronounced /məst/.
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 14782, this pair ranks #467,984 of 530,003 scored English confusable pairs - a relatively easy-to-tell-apart pair.
Frequency comparison
Frequently Asked Questions
Can "mast" and "must" be used interchangeably?
Remembering mast vs must
The fastest way to pick the right one every time.
- Check the role first: if you need a noun, it's “mast”; for a verb, it's “must”.
- See each word in full, definition, IPA, etymology and its other confusables. Full “mast” entry
- Browse more pairs most likely to be confused. Most confusable