Which to use
“ach” is a noun and “arco” is an adverb - they look or sound alike but fill different roles in a sentence.
- #30,673
- “ach” frequency rank
- #49,190
- “arco” frequency rank
- 79863
- confusion score
Side-by-Side Comparison
| Feature | ach | arco |
|---|---|---|
| Definition | Any of several species of plants, such as smallage, wild celery, parsley. | A note in string instrument musical notation indicating that the bow is to be used in the usual way, usually following a passage that is played pizzicato. |
Letter map: ach vs arco
Shared letters muted; letters that set ach and arco apart highlighted. Shared run: 2. ach runs 3 letters (VCC) against arco's 4 (VCCV) - the length gap alone is often enough to separate them once you know to check it.
Part-of-speech tell for ach / arco
Our dataset has no pronunciation recorded for both members, so the reliable separator here is grammatical: ach is anoun and arcoanadverb. On the page they differ by 1 letter(s) in length. Our composite confusion score for this pair is 79863, derived from the frequency rank of both members and their visual similarity.
ach is recorded at frequency rank #30,673, classified as anoun, pronounced /æt͡ʃ/. arco is at rank #49,190, tagged as anadv.
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 79863, this pair ranks #21,107 of 530,003 scored English confusable pairs - among the most confusable pairs.
Orthographic DNA of ach vs arco
Shared letters: ac. Private to "ach": h. Private to "arco": or.
"ach" · 3 letters · shape VCC · "arco" · 4 letters · shape VCCV
Known mistypes of this pair
- arco ← arcco · aroc · arrco · raco
Frequently Asked Questions
Is swapping "ach" for "arco" ever safe?
Which is more common, "ach" or "arco"?
Useful next steps
Pair "ach" vs "arco" is on the table, pick a follow-up below.
- Full dictionary entry for "ach" with definition, IPA, and generated misspellings. Word entry
- Full dictionary entry for "arco" - compare definitions side by side with the headword page. Word entry
- This pair ranks #21,107 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
- "ach" and "arco" also get mixed up with nearby pairs, the highest-scored neighbour is "algo vs arco". 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 #21,107 of 530,003 scored English pairs, corpus vintage 2026-09-03, not spelling advice.