hippocampus definition by American Heritage Dictionary
A ridge in the floor of each lateral ventricle of the brain that consists mainly of gray matter and has a central role in memory processes.
Origin: Late Latin, a sea horse with a horse's forelegs and a dolphin's tail (from its shape in cross section), from Greek hippokampos : hippos, horse; see ekwo- in Indo-European roots + kampos, sea monster.
The complex, internally convoluted structure that forms the medial margin of the cortical mantle of the cerebral hemisphere, borders the choroid fissure of the lateral ventricle, is composed of two gyri with their white matter, and forms part of the limbic system.
A convoluted, seahorse-shaped structure in the cerebral cortex of the temporal lobe of the brain, composed of two gyri with white matter above gray matter. It forms part of the limbic system and is involved in the processing of emotions and memory.