sea horse

noun

By · According to Wiktionary data (CC BY-SA) ·

"sea-horse" is a 8-letter English headword indexed on PlainSpell.

The verdict

“sea horse” is uncommon English (outside the top frequency list), classed as a noun. The kind of spelling people second-guess.

Unranked
below top-frequency English
9
letters

According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - Any of the small fish of the genus Hippocampus that have a horselike head and swim upright.

Key facts for sea horse
PropertyValue
Headwordsea horse
LanguageEnglish
Part of speechNoun
Letters9
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Where “sea horse” sits in English frequency

sea horse falls outside the top-100,000 ranked English words, the long-tail zone of technical, archaic, or low-frequency vocabulary, exactly where readers second-guess spellings most.

Beyond rank #100,000. Source: FrequencyWords open word-frequency list.

Rare enough to double-check

sea horse is uncommon English outside the top frequency list, classed as anoun. Rarity is why readers land here mid-draft. 5 senses are on record.

No generated misspelling entries exist for sea horse in our index, which points to an orthography that plays by predictable English rules. Our confusable-pair dataset has no match for it, a sign it's visually distinctive enough not to be mixed up with another word.

Etymologically, the entry records: From Middle English sehors (“walrus”), equivalent to sea + horse. Probably a calque of obsolete French cheval de mer or directly of Late Latin caballus marinus. The correct English form is sea horse, spelled S-E-A- -H-O-R-S-E.

Definition

  1. 1
    Any of the small fish of the genus Hippocampus that have a horselike head and swim upright.
  2. 2
    Any of a series of high-value British stamps issued during the reign of King George V, featuring a depiction of Britannia on a chariot in choppy seas.
  3. 3
    A hippopotamus.
  4. 4
    A walrus.
  5. 5
    Synonym of hippocampus.

Etymology

From Middle English sehors (“walrus”), equivalent to sea + horse. Probably a calque of obsolete French cheval de mer or directly of Late Latin caballus marinus.

This word in other languages

hipocampo(Español)hippocampe(Français)Seepferdchen(Deutsch)

Definitions, pronunciation, and etymology for this entry are drawn from Wiktionary via the kaikki.org structured extract (CC BY-SA). See the methodology for how each field is sourced and updated.

Frequently Asked Questions

How do you spell "sea horse"?
"sea horse" is spelled S-E-A- -H-O-R-S-E.
What does "sea horse" mean?
As a noun, "sea horse" means: Any of the small fish of the genus Hippocampus that have a horselike head and swim upright.
What is the origin of the word "sea horse"?
From Middle English sehors (“walrus”), equivalent to sea + horse. Probably a calque of obsolete French cheval de mer or directly of Late Latin caballus marinus. See the full etymology section above for more details.
Is PlainSpell free to use?
Yes, PlainSpell is a completely free word reference. You can look up definitions, pronunciations, confusable pairs, homophones, and spelling corrections across 5 languages without any sign-up or subscription.

Using “sea horse”

The practical upshot for anyone who landed here from a spell-check.

  • The one correct English spelling is S-E-A- -H-O-R-S-E - every other letter order is a misspelling in standard orthography.
  • Browse more English words and confusable pairs in the same reference. English words
Data Source

Wiktionary (via kaikki.org), licensed under CC BY-SA & GFDL. Word ordering uses an open word-frequency list; misspelling variants are generated by edit-distance from the correct headword.

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

Source: FrequencyWords open word-frequency list