Definify.com
Webster 1913 Edition
Sea horse
Sea′ horseˊ
.1.
A fabulous creature, half horse and half fish, represented in classic mythology as driven by sea dogs or ridden by the Nereids. It is also depicted in heraldry. See
Hippocampus
. 2.
(Zool.)
(a)
The walrus.
(b)
Any fish of the genus Hippocampus.
☞ In a passage of Dryden’s, the word is supposed to refer to the hippopotamus.