sevsseinWhat's the difference?

Quick tell: se is a conjunction, sein is a verb, so they fill different roles in a sentence.

Which to use

“se” is a conjunction and “sein” is a verb - they look or sound alike but fill different roles in a sentence.

#16
“se” frequency rank
#43,647
“sein” frequency rank
43663
confusion score

Side-by-Side Comparison

Feature se sein
Definition indica hipótese ser, estar.

Where the eye mixes se and sein

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

2 ch
se
4 ch
sein

Why the eye confuses se with sein

These two trip readers on the page rather than in the ear: se is /sɨ/ while sein is /zaɪ̯n/. Spoken aloud the problem disappears. In writing it persists, because they differ by 2 extra letter(s) - “se” sits inside “sein”, and the parts of speech differ too (conjunction vs verb), which is usually the fastest check. Our composite confusion score for this pair is 43663, derived from the frequency rank of both members and their visual similarity.

se is recorded at frequency rank #16, classified as aconj, pronounced /sɨ/. sein is at rank #43,647, tagged as averb, pronounced /zaɪ̯n/.

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 43663, this pair ranks #21,966 of 75,631 scored Portuguese confusable pairs - roughly mid-pack for confusability.

Orthographic DNA of se vs sein

Shared letters: es. Private to "se": -. Private to "sein": in.

"se" · 2 letters · shape CV  ·  "sein" · 4 letters · shape CVVC

Known mistypes of this pair

  • seinesin · seinn · seni · sien · ssein

Frequently Asked Questions

Is swapping "se" for "sein" ever safe?
No - they are not even the same part of speech. "se" is a conjunction and "sein" a verb, so a sentence built for one is usually ungrammatical with the other.
Which is more common, "se" or "sein"?
"se" is the more common of the two: it sits at frequency rank #16 in our Portuguese list, against #43,647 for "sein". That is a wide gap, so in ordinary text the rarer spelling is the one worth double-checking.

What to do next

Pronunciation already separates them, if the page still looks alike, the dictionary links below settle it.

  • Full dictionary entry for "se" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "sein" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #21,966 of 75,631 scored Portuguese confusable pairs in this corpus vintage. Corpus statistics
  • "se" and "sein" also get mixed up with nearby pairs, the highest-scored neighbour is "sein vs slip". 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 #21,966 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