mervsmmWhat's the difference?

Which to use

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

#21,067
“mer” frequency rank
#2,511
“mm” frequency rank
23578
confusion score

Side-by-Side Comparison

Feature mer mm
Definition Mar. Abreviatura de milímetro.

Where the eye mixes mer and mm

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

3 ch
mer
2 ch
mm

Why the eye confuses mer with mm

A purely visual mix-up. mer ([mɛʁ]) and mm ([ˈm]) 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 23578, derived from the frequency rank of both members and their visual similarity.

mer is recorded at frequency rank #21,067, classified as anoun, pronounced [mɛʁ]. mm is at rank #2,511, tagged as anoun, pronounced [ˈm].

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 23578, this pair ranks #245,131 of 323,831 scored Spanish confusable pairs - a relatively easy-to-tell-apart pair.

Orthographic DNA of mer vs mm

Shared letters: m. Private to "mer": er. Private to "mm": -.

"mer" · 3 letters · shape CVC  ·  "mm" · 2 letters · shape CC

Frequently Asked Questions

Is swapping "mer" for "mm" ever safe?
No. They are said differently ([mɛʁ] versus [ˈm]) and carry different meanings; reading the sentence aloud is usually enough to catch the wrong one.
Frequency check: "mer" vs "mm" - which ranks higher?
"mm" is the more common of the two: it sits at frequency rank #2,511 in our Spanish list, against #21,067 for "mer". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

Useful next steps

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

  • Full dictionary entry for "mer" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "mm" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #245,131 of 323,831 scored Spanish confusable pairs in this corpus vintage. Corpus statistics
  • "mer" and "mm" also get mixed up with nearby pairs, the highest-scored neighbour is "mer vs mur". Nearby pair

Confusion rank #245,131 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