som vs su, What's the Difference?

Which to use

“som” is a noun and “su” is an adjective - they look or sound alike but fill different roles in a sentence.

#1,134
“som” frequency rank: #6,713
“su” frequency rank: 7847
confusion score

Side-by-Side Comparison

Feature	som	su
Definition	onda longitudinal transmitida pela matéria e que podemos ouvir (geralmente entre 20Hz e 20kHz):	dele

Letter map: som vs su

Shared letters muted; letters that set som and su apart highlighted. Shared run: 1.

3 ch

som

2 ch

Role in the sentence - som and su

Our dataset has no pronunciation recorded for both members, so the reliable separator here is grammatical: som is anoun and suanadjective. On the page they differ by 1 letter(s) in length. Our composite confusion score for this pair is 7847, derived from the frequency rank of both members and their visual similarity.

som is recorded at frequency rank #1,134, classified as anoun, pronounced /ˈsõ/. su is at rank #6,713, tagged as anadj.

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 7847, this pair ranks #66,162 of 75,631 scored Portuguese confusable pairs - a relatively easy-to-tell-apart pair.

Orthographic DNA of som vs su

Shared letters: s. Private to "som": mo. Private to "su": u.

"som" · 3 letters · shape CVC · "su" · 2 letters · shape CV

Frequently Asked Questions

Is swapping "som" for "su" ever safe?

No - they are not even the same part of speech. "som" is a noun and "su" an adjective, so a sentence built for one is usually ungrammatical with the other.

In ordinary Portuguese text, does "som" or "su" show up more?

"som" is the more common of the two: it sits at frequency rank #1,134 in our Portuguese list, against #6,713 for "su". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

What to do next

You've compared "som" and "su". Here's where to go from here.

Full dictionary entry for "som" with definition, IPA, and generated misspellings. Word entry
Full dictionary entry for "su" - compare definitions side by side with the headword page. Word entry
This pair ranks #66,162 of 75,631 scored Portuguese confusable pairs in this corpus vintage. Corpus statistics
"som" and "su" also get mixed up with nearby pairs, the highest-scored neighbour is "Sau vs su". Nearby pair

Confusion rank #66,162 of 75,631 scored Portuguese pairs, corpus vintage 2026-09-03, not spelling advice.