Which to use
“octagon” is a noun and “octagonal” is an adjective - they look or sound alike but fill different roles in a sentence.
- #32,520
- “octagon” frequency rank
- #44,380
- “octagonal” frequency rank
- 76900
- confusion score
Side-by-Side Comparison
| Feature | octagon | octagonal |
|---|---|---|
| Definition | A polygon with eight sides and eight angles. | Shaped like an octagon, in having eight sides and eight angles. |
Where the spellings diverge
Shared letters are muted; the letters that actually set octagon and octagonal apart are highlighted. They share 7 letters in sequence, which is exactly why the eye skips the difference.
Spelling & Dictionary Insight
These two trip readers on the page rather than in the ear: octagon is /ˈɒktəɡ(ə)n/ while octagonal is /ɑkˈtæɡənəl/. Spoken aloud the problem disappears. In writing it persists, because they differ by 2 extra letter(s) - “octagon” sits inside “octagonal”, and the parts of speech differ too (noun vs adjective), which is usually the fastest check. Our composite confusion score for this pair is 76900, derived from the frequency rank of both members and their visual similarity.
octagon is recorded at frequency rank #32,520, classified as anoun, pronounced /ˈɒktəɡ(ə)n/. octagonal is at rank #44,380, tagged as anadj, pronounced /ɑkˈtæɡənəl/.
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 76900, this pair ranks #28,803 of 530,003 scored English confusable pairs - among the most confusable pairs.
Orthographic DNA of octagon vs octagonal
Shared letters: acgnot. Private to "octagon": -. Private to "octagonal": l.
"octagon" · 7 letters · shape VCCVCVC · "octagonal" · 9 letters · shape VCCVCVCVC
Known mistypes of this pair
Frequency comparison
Frequently Asked Questions
Can "octagon" and "octagonal" be used interchangeably?
Which is more common, "octagon" or "octagonal"?
Remembering octagon vs octagonal
The fastest way to pick the right one every time.
- Check the role first: if you need a noun, it's “octagon”; for an adjective, it's “octagonal”.
- See each word in full, definition, IPA, etymology and its other confusables. Full “octagon” entry
- Browse more pairs most likely to be confused. Most confusable