psivsWhat's the difference?

Quick tell: psi is a noun, is an adverb, so they fill different roles in a sentence.

Which to use

“psi” is a noun and “sí” is an adverb - they look or sound alike but fill different roles in a sentence.

#36,774
“psi” frequency rank
#146
“sí” frequency rank
36920
confusion score

Side-by-Side Comparison

Feature psi
Definition Letra del alfabeto griego (Ψψ). Palabra usada para expresar afirmación.

Same sound, different letters: psi vs sí

Muted letters are shared; highlighted letters are the only spelling cue when pronunciation matches. Shared run: 1 letter.

3 ch
psi
2 ch
sí

Ear matches; page differs - psi and sí

Say them out loud and nothing separates them: psi and carry the same recorded pronunciation, [ˈsi]. Grammar is what tells them apart: one is anoun, the other anadverb, so most sentences will only accept one of them. They differ by 1 letter(s) in length. Our composite confusion score for this pair is 36920, derived from the frequency rank of both members and their visual similarity.

psi is recorded at frequency rank #36,774, classified as anoun, pronounced [ˈsi]. is at rank #146, tagged as anadv, pronounced [ˈsi].

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 36920, this pair ranks #178,084 of 323,831 scored Spanish confusable pairs - roughly mid-pack for confusability.

Orthographic DNA of psi vs sí

Shared letters: s. Private to "psi": ip. Private to "sí": í.

"psi" · 3 letters · shape CCV  ·  "sí" · 2 letters · shape CV

Frequently Asked Questions

Do "psi" and "sí" mean the same thing in a sentence?
No - they are not even the same part of speech. "psi" is a noun and "sí" an adverb, so a sentence built for one is usually ungrammatical with the other.
Which is more common, "psi" or "sí"?
"sí" is the more common of the two: it sits at frequency rank #146 in our Spanish list, against #36,774 for "psi". That is a wide gap, so in ordinary text the rarer spelling is the one worth double-checking.

What to do next

Sound matches; spelling doesn't. Use the exits below to lock the right form or check a cousin pair.

  • Full dictionary entry for "psi" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "sí" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #178,084 of 323,831 scored Spanish confusable pairs in this corpus vintage. Corpus statistics
  • "psi" and "sí" also get mixed up with nearby pairs, the highest-scored neighbour is "PRC vs psi". Nearby pair

Confusion rank #178,084 of 323,831 scored Spanish pairs, corpus vintage 2026-09-03, not spelling advice.

Source: Wiktionary (via kaikki.org) Structured Wiktionary extract

Source: FrequencyWords open word-frequency list