noun. plural, hippocampi
In anatomy, the hippocampus is an elongated ridge of the brain, found in each lateral ventricle (and shaped a bit like a seahorse or whale). Its function is believed to be the center of emotion, memory, and the involuntary actions of the nervous system.
People with Alzheimer's disease are shown to have damage to their hippocampus, which leads to memory loss and disorientation.
Humans have two hippocampi, one of each side of the brain.