hippocampus Definition

hippocampus
noun hippocampi

1. mythol.
A fish-tailed sea monster with a horse-like head and neck.
2. A genus of small fishes with a horse-like head and neck. Also called sea horse.
3. anatomy.
A structure in the vertebrate brain consisting of two curved ridges across the ventricles, associated with emotional responses.

Etymology: 16c: from Greek hippos horse + kampos sea-monster.