seas vs sei, What's the Difference?

Which to use

“seas” is a verb and “sei” is a num - they look or sound alike but fill different roles in a sentence.

#2,050
“seas” frequency rank: #48,072
“sei” frequency rank: 50122
confusion score

Side-by-Side Comparison

Feature	seas	sei
Definition	Segunda persona del singular (tú) del presente de subjuntivo de ser.	Seis.

Where the spellings diverge

Shared letters are muted; the letters that actually set seas and sei apart are highlighted. They share 2 letters in sequence, which is exactly why the eye skips the difference.

4 ch

seas

3 ch

sei

Spelling & Dictionary Insight

These two trip readers on the page rather than in the ear: seas is [ˈseas] while sei is /s̺ej/. Spoken aloud the problem disappears. In writing it persists, because they differ by 1 letter(s) in length, and the parts of speech differ too (verb vs num), which is usually the fastest check. Our composite confusion score for this pair is 50122, derived from the frequency rank of both members and their visual similarity.

seas is recorded at frequency rank #2,050, classified as averb, pronounced [ˈseas]. sei is at rank #48,072, tagged as anum, pronounced /s̺ej/.

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 50122, this pair ranks #104,960 of 323,831 scored Spanish confusable pairs - roughly mid-pack for confusability.

Orthographic DNA of seas vs sei

Shared letters: es. Private to "seas": a. Private to "sei": i.

"seas" · 4 letters · shape CVVC · "sei" · 3 letters · shape CVV

Known mistypes of this pair

seas ← ceas · saes · seass · sesa · sseas

Frequency comparison

seas#2,050

sei#48,072

Source: FrequencyWords open word-frequency list

Frequently Asked Questions

Can "seas" and "sei" be used interchangeably?

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

Which is more common, "seas" or "sei"?

"seas" is the more common of the two: it sits at frequency rank #2,050 in our Spanish list, against #48,072 for "sei". That is a wide gap, so in ordinary text the rarer spelling is the one worth double-checking.

Remembering seas vs sei

The fastest way to pick the right one every time.

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