also: うみうま
noun
Common name for the marine fish. The reading かいば is standard; うみうま is a rare alternative.
See also: タツノオトシゴ
水族館で海馬を見た。
I saw a seahorse at the aquarium.
noun
hippocampus
Only with reading かいば
Anatomical term for the part of the brain. Only read かいば.
海馬は記憶に重要な役割を果たす。
The hippocampus plays an important role in memory.
noun
walrus
Only with reading かいば
Rare alternative name for walrus, usually called セイウチ. Only read かいば.
See also: セイウチ
古い文献では海馬がセイウチを指すことがある。
In old documents, 海馬 can refer to a walrus.
Kun'yomi reading for the seahorse sense; rarely used in modern Japanese.
Sino-Japanese compound 海 (sea) + 馬 (horse), calque of the seahorse's shape. The hippocampus sense is a direct borrowing of the anatomical term, which itself is named after the seahorse-like shape of the brain structure. The walrus sense is an archaic usage, possibly from a different etymological association.