sem vs som, What's the Difference?

Which to use

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

#69
“sem” frequency rank: #1,134
“som” frequency rank: 1203
confusion score

Side-by-Side Comparison

Feature	sem	som
Definition	indicativa de carência ou ausência	onda longitudinal transmitida pela matéria e que podemos ouvir (geralmente entre 20Hz e 20kHz):

Where the eye mixes sem and som

Muted = shared; highlighted = the visual trap. They share 2 letters in sequence.

3 ch

sem

3 ch

som

Visual trap between sem and som

These two trip readers on the page rather than in the ear: sem is /sɐ̃j̃/ while som is /ˈsõ/. Spoken aloud the problem disappears. In writing it persists, because they differ by a single letter - e in “sem” becomes o in “som”, and the parts of speech differ too (preposition vs noun), which is usually the fastest check. Our composite confusion score for this pair is 1203, derived from the frequency rank of both members and their visual similarity.

sem is recorded at frequency rank #69, classified as aprep, pronounced /sɐ̃j̃/. som is at rank #1,134, tagged as anoun, pronounced /ˈsõ/.

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 1203, this pair ranks #74,389 of 75,631 scored Portuguese confusable pairs - a relatively easy-to-tell-apart pair.

Orthographic DNA of sem vs som

Shared letters: ms. Private to "sem": e. Private to "som": o.

"sem" · 3 letters · shape CVC · "som" · 3 letters · shape CVC

Frequently Asked Questions

Can "sem" and "som" be used interchangeably?

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

Frequency check: "sem" vs "som" - which ranks higher?

"sem" is the more common of the two: it sits at frequency rank #69 in our Portuguese list, against #1,134 for "som". That is a wide gap, so in ordinary text the rarer spelling is the one worth double-checking.

After this comparison

Eye-level mix-up between "sem" and "som" is sorted above. Next: full entries or other pairs that share a letter shape.

Full dictionary entry for "sem" with definition, IPA, and generated misspellings. Word entry
Full dictionary entry for "som" - compare definitions side by side with the headword page. Word entry
This pair ranks #74,389 of 75,631 scored Portuguese confusable pairs in this corpus vintage. Corpus statistics
"sem" and "som" also get mixed up with nearby pairs, the highest-scored neighbour is "soap vs som". Nearby pair

Confusion rank #74,389 of 75,631 scored Portuguese pairs, corpus vintage 2026-09-03, not spelling advice.