sig vs su, What's the Difference?

Which to use

“sig” is a contraction and “su” is an adjective - they look or sound alike but fill different roles in a sentence.

#22,189
“sig” frequency rank: #20
“su” frequency rank: 22209
confusion score

Side-by-Side Comparison

Feature	sig	su
Definition	Contracción de signature (firma).	Adjetivo posesivo de la tercera persona; de él, de ella, de ellos, de ellas.

Where the eye mixes sig and su

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

3 ch

sig

2 ch

Why the eye confuses sig with su

These two trip readers on the page rather than in the ear: sig is /sɪɡ/ while su is [su]. 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 (contraction vs adjective), which is usually the fastest check. Our composite confusion score for this pair is 22209, derived from the frequency rank of both members and their visual similarity.

sig is recorded at frequency rank #22,189, classified as acontraction, pronounced /sɪɡ/. su is at rank #20, tagged as anadj, pronounced [su].

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 22209, this pair ranks #251,407 of 323,831 scored Spanish confusable pairs - a relatively easy-to-tell-apart pair.

Orthographic DNA of sig vs su

Shared letters: s. Private to "sig": gi. Private to "su": u.

"sig" · 3 letters · shape CVC · "su" · 2 letters · shape CV

Frequently Asked Questions

Do "sig" and "su" mean the same thing in a sentence?

No - they are not even the same part of speech. "sig" is a contraction and "su" an adjective, so a sentence built for one is usually ungrammatical with the other.

In ordinary Spanish text, does "sig" or "su" show up more?

"su" is the more common of the two: it sits at frequency rank #20 in our Spanish list, against #22,189 for "sig". That is a wide gap, so in ordinary text the rarer spelling is the one worth double-checking.

Useful next steps

Eye-level mix-up between "sig" and "su" is sorted above. Next: full entries or other pairs that share a letter shape.

Full dictionary entry for "sig" with definition, IPA, and generated misspellings. Word entry
Full dictionary entry for "su" - compare definitions side by side with the headword page. Word entry
This pair ranks #251,407 of 323,831 scored Spanish confusable pairs in this corpus vintage. Corpus statistics
"sig" and "su" also get mixed up with nearby pairs, the highest-scored neighbour is "sig vs sila". Nearby pair

Confusion rank #251,407 of 323,831 scored Spanish pairs, corpus vintage 2026-09-03, not spelling advice.