caívsCDWhich spelling fits?

Quick tell: caí is a verb, CD is a noun, so they fill different roles in a sentence.

Which to use

“caí” is a verb and “CD” is a noun - they look or sound alike but fill different roles in a sentence.

#11,538
“caí” frequency rank
#4,403
“CD” frequency rank
15941
confusion score

Side-by-Side Comparison

Feature caí CD
Definition Primera persona del singular (yo) del pretérito perfecto simple de indicativo de caer o de caerse. Disco de plástico, de 12 cm de diámetro, recubierto con una delgada capa de aluminio usada para grabar datos en formato digital para ser leído mediante el reflejo de un láser en su superficie. Se emplean para la grabación de música y datos

Where the eye mixes caí and CD

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

3 ch
caí
2 ch
CD

Why the eye confuses caí with CD

These two trip readers on the page rather than in the ear: caí is [kaˈi] while CD is [seˈð̞e]. 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 noun), which is usually the fastest check. Our composite confusion score for this pair is 15941, derived from the frequency rank of both members and their visual similarity.

caí is recorded at frequency rank #11,538, classified as averb, pronounced [kaˈi]. CD is at rank #4,403, tagged as anoun, pronounced [seˈð̞e].

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 15941, this pair ranks #278,152 of 323,831 scored Spanish confusable pairs - a relatively easy-to-tell-apart pair.

Orthographic DNA of caí vs CD

Shared letters: c. Private to "caí": . Private to "CD": d.

"caí" · 3 letters · shape CVV  ·  "CD" · 2 letters · shape CC

Frequently Asked Questions

Can "caí" and "CD" be used interchangeably?
No - they are not even the same part of speech. "caí" is a verb and "CD" a noun, so a sentence built for one is usually ungrammatical with the other.
Frequency check: "caí" vs "CD" - which ranks higher?
"CD" is the more common of the two: it sits at frequency rank #4,403 in our Spanish list, against #11,538 for "caí". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

Useful next steps

Visual near-miss handled. Browse the word pages or a neighbour when the next look-alike shows up.

  • Full dictionary entry for "caí" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "CD" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #278,152 of 323,831 scored Spanish confusable pairs in this corpus vintage. Corpus statistics
  • "caí" and "CD" also get mixed up with nearby pairs, the highest-scored neighbour is "caí vs cuc". Nearby pair

Confusion rank #278,152 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