Which to use
“thorough” is an adjective and “trough” is a noun - they look or sound alike but fill different roles in a sentence.
- #7,512
- “thorough” frequency rank
- #16,606
- “trough” frequency rank
- 24118
- confusion score
Side-by-Side Comparison
| Feature | thorough | trough |
|---|---|---|
| Definition | Painstaking and careful not to miss or omit any detail. | A long, narrow container, open on top, for feeding or watering animals. |
Where the eye mixes thorough and trough
Muted = shared; highlighted = the visual trap. They share 6 letters in sequence. thorough runs 8 letters (CCVCVVCC) against trough's 6 (CCVVCC) - the length gap alone is often enough to separate them once you know to check it.
Why the eye confuses thorough with trough
These two trip readers on the page rather than in the ear: thorough is /ˈθʌɹə/ while trough is /tɹɒf/. Spoken aloud the problem disappears. In writing it persists, because they differ by 2 letter(s) in length, and the parts of speech differ too (adjective vs noun), which is usually the fastest check. Our composite confusion score for this pair is 24118, derived from the frequency rank of both members and their visual similarity.
thorough is recorded at frequency rank #7,512, classified as anadj, pronounced /ˈθʌɹə/. trough is at rank #16,606, tagged as anoun, pronounced /tɹɒf/.
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 24118, this pair ranks #404,318 of 530,003 scored English confusable pairs - a relatively easy-to-tell-apart pair.
Orthographic DNA of thorough vs trough
Shared letters: ghortu. Private to "thorough": -. Private to "trough": -.
"thorough" · 8 letters · shape CCVCVVCC · "trough" · 6 letters · shape CCVVCC
Known mistypes of this pair
Frequently Asked Questions
Can "thorough" and "trough" be used interchangeably?
Which is more common, "thorough" or "trough"?
What to do next
Visual near-miss handled. Browse the word pages or a neighbour when the next look-alike shows up.
- Full dictionary entry for "thorough" with definition, IPA, and generated misspellings. Word entry
- Full dictionary entry for "trough" - compare definitions side by side with the headword page. Word entry
- This pair ranks #404,318 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
- "thorough" and "trough" also get mixed up with nearby pairs, the highest-scored neighbour is "trough vs troupe". 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 #404,318 of 530,003 scored English pairs, corpus vintage 2026-09-03, not spelling advice.