Which to use
“alum” and “annum” are a confusable English pair: similar on the page, but distinct in meaning, check the gloss before you choose.
- #20,832
- “alum” frequency rank
- #21,439
- “annum” frequency rank
- 42271
- confusion score
Side-by-Side Comparison
| Feature | alum | annum |
|---|---|---|
| Definition | An astringent salt, usually occurring in the form of pale crystals, much used in the dyeing and tanning trade and in certain medicines, and now understood to be a double sulphate of potassium and aluminium (K₂SO₄·Al₂(SO₄)₃·24H₂O). | Synonym of year. |
Where the spellings diverge
Shared letters are muted; the letters that actually set alum and annum apart are highlighted. They share 3 letters in sequence, which is exactly why the eye skips the difference.
Spelling & Dictionary Insight
alum and annum 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 42271, derived from the frequency rank of both members and their visual similarity.
alum is recorded at frequency rank #20,832, classified as anoun, pronounced /ˈæl.əm/. annum is at rank #21,439, tagged as anoun.
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 42271, this pair ranks #250,749 of 530,003 scored English confusable pairs - roughly mid-pack for confusability.
Frequency comparison
Frequently Asked Questions
Can "alum" and "annum" be used interchangeably?
Remembering alum vs annum
The fastest way to pick the right one every time.
- Read both glosses above and match the meaning you intend, only context separates this pair.
- See each word in full, definition, IPA, etymology and its other confusables. Full “alum” entry
- Browse more pairs most likely to be confused. Most confusable