seahorse

Noun

sea horse (plural sea horses)

1. Any of the small fish of the genus Hippocampus that have a horselike head and swim upright.
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. (obsolete) A hippopotamus.
   • As most authors mention the hippopotamus under the names of the sea-horse, or the sea-cow, he has sometimes been confounded with the latter, which inhabits only the northern seas.1830, Georges Louis Le Clerc (Count de Buffon), The Natural History of Quadrupeds (page 331)
4. (obsolete) A walrus.
   • One morning we had vast quantities of sea-horses about the ship, which neighed exactly like any other horses.1789, Olaudah Equiano, chapter 9, in The Interesting Narrative, volume I
5. Synonym of hippocampus.
   • In the middle of each of theſe four little Gardens, there is a diſtinct Fountain, and in each of the Fountains there is placed a gilded Triton, ſitting on a gilded Sea-Horſe, or on a Sea-Goat, all upon Rockwork, like that in the middle Fountain[.]1699, Walter Harris, A Description of the King's Royal Palace and Gardens at Loo, London: R. Roberts, page 31

   Synonyms:

   hippocampus