scivssemWhich spelling fits?

Quick tell: sci is a noun, sem is a preposition, so they fill different roles in a sentence.

Which to use

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

#29,904
“sci” frequency rank
#69
“sem” frequency rank
29973
confusion score

Side-by-Side Comparison

Feature sci sem
Definition esqui, placa geralmente de madeira para deslizar na água ou na neve indicativa de carência ou ausência

Where the eye mixes sci and sem

Muted = shared; highlighted = the visual trap. They share 1 letter in sequence.

3 ch
sci
3 ch
sem

Visual trap between sci and sem

These two trip readers on the page rather than in the ear: sci is /ˈʃi/ while sem is /sɐ̃j̃/. Spoken aloud the problem disappears. In writing it persists, because they share most of their letters but differ in 2 positions, and the parts of speech differ too (noun vs preposition), which is usually the fastest check. Our composite confusion score for this pair is 29973, derived from the frequency rank of both members and their visual similarity.

sci is recorded at frequency rank #29,904, classified as anoun, pronounced /ˈʃi/. sem is at rank #69, tagged as aprep, pronounced /sɐ̃j̃/.

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 29973, this pair ranks #38,511 of 75,631 scored Portuguese confusable pairs - roughly mid-pack for confusability.

Orthographic DNA of sci vs sem

Shared letters: s. Private to "sci": ci. Private to "sem": em.

"sci" · 3 letters · shape CCV  ·  "sem" · 3 letters · shape CVC

Frequently Asked Questions

Do "sci" and "sem" mean the same thing in a sentence?
No - they are not even the same part of speech. "sci" is a noun and "sem" a preposition, so a sentence built for one is usually ungrammatical with the other.
Which is more common, "sci" or "sem"?
"sem" is the more common of the two: it sits at frequency rank #69 in our Portuguese list, against #29,904 for "sci". That is a wide gap, so in ordinary text the rarer spelling is the one worth double-checking.

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 "sci" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "sem" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #38,511 of 75,631 scored Portuguese confusable pairs in this corpus vintage. Corpus statistics
  • "sci" and "sem" also get mixed up with nearby pairs, the highest-scored neighbour is "Sau vs sci". Nearby pair

Confusion rank #38,511 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