sein vs sino, What's the Difference?

Which to use

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

#45,601
“sein” frequency rank: #210
“sino” frequency rank: 45811
confusion score

Side-by-Side Comparison

Feature	sein	sino
Definition	Ser, estar.	Si aparece en preguntas o precedido de negación expletiva, indica que una única persona cumple con lo expresado.

Where the spellings diverge

Shared letters are muted; the letters that actually set sein and sino apart are highlighted. They share 3 letters in sequence, which is exactly why the eye skips the difference.

4 ch

sein

4 ch

sino

Spelling & Dictionary Insight

These two trip readers on the page rather than in the ear: sein is [ˈzaɪ̯n] while sino is [ˈsino]. Spoken aloud the problem disappears. In writing it persists, because they share most of their letters but differ in 3 positions, and the parts of speech differ too (verb vs conjunction), which is usually the fastest check. Our composite confusion score for this pair is 45811, derived from the frequency rank of both members and their visual similarity.

sein is recorded at frequency rank #45,601, classified as averb, pronounced [ˈzaɪ̯n]. sino is at rank #210, tagged as aconj, pronounced [ˈsino].

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 45811, this pair ranks #129,319 of 323,831 scored Spanish confusable pairs - roughly mid-pack for confusability.

Orthographic DNA of sein vs sino

Shared letters: ins. Private to "sein": e. Private to "sino": o.

"sein" · 4 letters · shape CVVC · "sino" · 4 letters · shape CVCV

Known mistypes of this pair

sein ← esin · seinn · seni · ssein
sino ← cino · isno · sinno · snio · ssino

Frequency comparison

sein#45,601

sino#210

Source: FrequencyWords open word-frequency list

Frequently Asked Questions

Can "sein" and "sino" be used interchangeably?

No - they are not even the same part of speech. "sein" is a verb and "sino" a conjunction, so a sentence built for one is usually ungrammatical with the other.

Which is more common, "sein" or "sino"?

"sino" is the more common of the two: it sits at frequency rank #210 in our Spanish list, against #45,601 for "sein". That is a wide gap, so in ordinary text the rarer spelling is the one worth double-checking.

Remembering sein vs sino

The fastest way to pick the right one every time.

Check the role first: if you need a verb, it's “sein”; for a conjunction, it's “sino”.
See each word in full, definition, IPA, etymology and its other confusables. Full “sein” entry
Browse more pairs most likely to be confused. Most confusable