Which to use
“fitter” is a noun and “foster” is an adjective - they look or sound alike but fill different roles in a sentence.
- #28,549
- “fitter” frequency rank
- #4,085
- “foster” frequency rank
- 32634
- confusion score
Side-by-Side Comparison
| Feature | fitter | foster |
|---|---|---|
| Definition | A person who fits or assembles something. | Providing parental care to children not related to oneself. |
Where the eye mixes fitter and foster
Muted = shared; highlighted = the visual trap. They share 4 letters in sequence. fitter and foster follow the identical consonant-vowel pattern (CVCCVC). Same shape at a glance is often the real trap, independent of shared letters.
Look-alike desk: fitter vs foster
These two trip readers on the page rather than in the ear: fitter is /ˈfɪtə(ɹ)/ while foster is /ˈfɒs.tə/. Spoken aloud the problem disappears. In writing it persists, because they share most of their letters but differ in 2 positions, and the parts of speech differ too (noun vs adjective), which is usually the fastest check. Our composite confusion score for this pair is 32634, derived from the frequency rank of both members and their visual similarity.
fitter is recorded at frequency rank #28,549, classified as anoun, pronounced /ˈfɪtə(ɹ)/. foster is at rank #4,085, tagged as anadj, pronounced /ˈfɒs.tə/.
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 32634, this pair ranks #336,182 of 530,003 scored English confusable pairs - roughly mid-pack for confusability.
Orthographic DNA of fitter vs foster
Shared letters: efrt. Private to "fitter": i. Private to "foster": os.
"fitter" · 6 letters · shape CVCCVC · "foster" · 6 letters · shape CVCCVC
Known mistypes of this pair
Frequently Asked Questions
Is swapping "fitter" for "foster" ever safe?
In ordinary English text, does "fitter" or "foster" show up more?
What to do next
Eye-level mix-up between "fitter" and "foster" is sorted above. Next: full entries or other pairs that share a letter shape.
- Full dictionary entry for "fitter" with definition, IPA, and generated misspellings. Word entry
- Full dictionary entry for "foster" - compare definitions side by side with the headword page. Word entry
- This pair ranks #336,182 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
- "fitter" and "foster" also get mixed up with nearby pairs, the highest-scored neighbour is "fitter vs fiver". 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 #336,182 of 530,003 scored English pairs, corpus vintage 2026-09-03, not spelling advice.