cemvscumWhat's the difference?

Quick tell: cem is a num, cum is a preposition, so they fill different roles in a sentence.

Which to use

“cem” is a num and “cum” is a preposition - they look or sound alike but fill different roles in a sentence.

#3,188
“cem” frequency rank
#29,299
“cum” frequency rank
32487
confusion score

Side-by-Side Comparison

Feature cem cum
Definition número equivalente a dez dezenas; cardinalidade de um conjunto que contenha uma centena de elementos distintos; representado pelo símbolo 100 (algarismos arábicos) ou C (algarismos romanos) usado para indicar algo com duas funções, ou então que tenha se modificado de uma coisa para outra:

Where the eye mixes cem and cum

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

3 ch
cem
3 ch
cum

Why the eye confuses cem with cum

These two trip readers on the page rather than in the ear: cem is /ˈsɐ̃j̃/ while cum is /kʌm/. Spoken aloud the problem disappears. In writing it persists, because they differ by a single letter - e in “cem” becomes u in “cum”, and the parts of speech differ too (num vs preposition), which is usually the fastest check. Our composite confusion score for this pair is 32487, derived from the frequency rank of both members and their visual similarity.

cem is recorded at frequency rank #3,188, classified as anum, pronounced /ˈsɐ̃j̃/. cum is at rank #29,299, tagged as aprep, pronounced /kʌm/.

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 32487, this pair ranks #35,310 of 75,631 scored Portuguese confusable pairs - roughly mid-pack for confusability.

Orthographic DNA of cem vs cum

Shared letters: cm. Private to "cem": e. Private to "cum": u.

"cem" · 3 letters · shape CVC  ·  "cum" · 3 letters · shape CVC

Frequently Asked Questions

Do "cem" and "cum" mean the same thing in a sentence?
No - they are not even the same part of speech. "cem" is a num and "cum" a preposition, so a sentence built for one is usually ungrammatical with the other.
Frequency check: "cem" vs "cum" - which ranks higher?
"cem" is the more common of the two: it sits at frequency rank #3,188 in our Portuguese list, against #29,299 for "cum". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

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 "cem" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "cum" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #35,310 of 75,631 scored Portuguese confusable pairs in this corpus vintage. Corpus statistics
  • "cem" and "cum" also get mixed up with nearby pairs, the highest-scored neighbour is "cham vs cum". Nearby pair

Confusion rank #35,310 of 75,631 scored Portuguese pairs, corpus vintage 2026-09-03, not spelling advice.

Source: Wiktionary (via kaikki.org) Structured Wiktionary extract

Source: FrequencyWords open word-frequency list