Which to use
“firstly” is an adverb and “firsts” is a noun - they look or sound alike but fill different roles in a sentence.
- #10,694
- “firstly” frequency rank
- #30,422
- “firsts” frequency rank
- 41116
- confusion score
Side-by-Side Comparison
| Feature | firstly | firsts |
|---|---|---|
| Definition | In the first place; before anything else; first. | plural of first |
Where the eye mixes firstly and firsts
Muted = shared; highlighted = the visual trap. They share 5 letters in sequence.
Visual trap between firstly and firsts
These two trip readers on the page rather than in the ear: firstly is /ˈfɜɹstli/ while firsts is /fɜːsts/. Spoken aloud the problem disappears. In writing it persists, because they differ by 1 letter(s) in length, and the parts of speech differ too (adverb vs noun), which is usually the fastest check. Our composite confusion score for this pair is 41116, derived from the frequency rank of both members and their visual similarity.
firstly is recorded at frequency rank #10,694, classified as anadv, pronounced /ˈfɜɹstli/. firsts is at rank #30,422, tagged as anoun, pronounced /fɜːsts/.
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 41116, this pair ranks #261,356 of 530,003 scored English confusable pairs - roughly mid-pack for confusability.
Orthographic DNA of firstly vs firsts
Shared letters: first. Private to "firstly": ly. Private to "firsts": -.
"firstly" · 7 letters · shape CVCCCCV · "firsts" · 6 letters · shape CVCCCC
Known mistypes of this pair
Frequently Asked Questions
Do "firstly" and "firsts" mean the same thing in a sentence?
Frequency check: "firstly" vs "firsts" - which ranks higher?
After this comparison
Visual near-miss handled. Browse the word pages or a neighbour when the next look-alike shows up.
- Full dictionary entry for "firstly" with definition, IPA, and generated misspellings. Word entry
- Full dictionary entry for "firsts" - compare definitions side by side with the headword page. Word entry
- This pair ranks #261,356 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
- "firstly" and "firsts" also get mixed up with nearby pairs, the highest-scored neighbour is "firsts vs frets". Nearby pair
- Recorded mistypes exist for at least one side of this pair, useful when a spell-checker or OCR lands on the wrong form. See mistypes
Confusion rank #261,356 of 530,003 scored English pairs, corpus vintage 2026-09-03, not spelling advice.