Meaning

noun a complex neural structure (shaped like a sea horse) consisting of grey matter and located on the floor of each lateral ventricle; intimately involved in motivation and emotion as part of the limbic s

noun seahorses

originFrom Late Latin hippocampus, from Ancient Greek ἱππόκαμπος (hippókampos, from ῐ̔́ππος (hĭ́ppos, “horse”) + κάμπος (kámpos, “sea-monster”)). The anatomy sense is so named from its resemblance to the seahorse. By surface analysis, hippo- + campus.

Etymology from Wiktionary, CC BY-SA 3.0