casillavscostillaTell them apart

Which to use

“casilla” and “costilla” are a confusable Spanish pair: similar on the page, but distinct in meaning, check the gloss before you choose.

#10,993
“casilla” frequency rank
#21,283
“costilla” frequency rank
32276
confusion score

Side-by-Side Comparison

Feature casilla costilla
Definition Cada división de las que se compone un casillero. Hueso largo y curvo que da forma y estructura al tórax

Where the eye mixes casilla and costilla

Muted = shared; highlighted = the visual trap. They share 6 letters in sequence. casilla runs 7 letters (CVCVCCV) against costilla's 8 (CVCCVCCV) - the length gap alone is often enough to separate them once you know to check it.

7 ch
casilla
8 ch
costilla

Visual trap between casilla and costilla

A purely visual mix-up. casilla ([kaˈsiʝa]) and costilla ([kosˈt̪iʝa]) are said differently, so reading them aloud is the quickest way to catch the wrong one. On the page they stay close: they differ by 1 letter(s) in length. Our composite confusion score for this pair is 32276, derived from the frequency rank of both members and their visual similarity.

casilla is recorded at frequency rank #10,993, classified as anoun, pronounced [kaˈsiʝa]. costilla is at rank #21,283, tagged as anoun, pronounced [kosˈt̪iʝa].

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 32276, this pair ranks #202,816 of 323,831 scored Spanish confusable pairs - roughly mid-pack for confusability.

Orthographic DNA of casilla vs costilla

Shared letters: acils. Private to "casilla": -. Private to "costilla": ot.

"casilla" · 7 letters · shape CVCVCCV  ·  "costilla" · 8 letters · shape CVCCVCCV

Known mistypes of this pair

  • casilla ← acsilla · cacilla · caislla · casila · casilal · caslila · cassilla · ccasilla
  • costilla ← ccostilla · cositlla · cosstilla · costila · costilal · costlila · costtilla · cotsilla

Frequently Asked Questions

Is swapping "casilla" for "costilla" ever safe?
No. They are said differently ([kaˈsiʝa] versus [kosˈt̪iʝa]) and carry different meanings; reading the sentence aloud is usually enough to catch the wrong one.
In ordinary Spanish text, does "casilla" or "costilla" show up more?
"casilla" is the more common of the two: it sits at frequency rank #10,993 in our Spanish list, against #21,283 for "costilla". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

After this comparison

Pronunciation already separates them, if the page still looks alike, the dictionary links below settle it.

  • Full dictionary entry for "casilla" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "costilla" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #202,816 of 323,831 scored Spanish confusable pairs in this corpus vintage. Corpus statistics
  • "casilla" and "costilla" also get mixed up with nearby pairs, the highest-scored neighbour is "canillas vs casilla". Nearby pair
  • Recorded mistypes exist for at least one side of this pair, useful when a spell-checker or OCR lands on the wrong form. See mistypes

Confusion rank #202,816 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