hippocampus

noun

hip·​po·​cam·​pus ˌhi-pə-ˈkam-pəs 

plural hippocampi ˌhi-pə-ˈkam-ˌpī  -(ˌ)pē 

: a curved elongated ridge that extends over the floor of the descending horn of each lateral ventricle of the brain, that consists of gray matter covered on the ventricular surface with white matter, and that is involved in forming, storing, and processing memory

hippocampal

ˌhi-pə-ˈkam-pəl 

adjective

Examples of hippocampus in a Sentence

Recent Examples on the Web

Stress can lead to shrinkage in specific areas of the brain, such as the hippocampus, while also causing negative changes in the prefrontal cortex and the amygdala. —Angelica Bottaro, Verywell Health, 6 Nov. 2025

The researchers found that the larger the activity boost in both the VOTC and the hippocampus during the initial insight, the better participants remembered the Mooney images. —Nora Bradford, Quanta Magazine, 5 Nov. 2025

People taking the twice-daily pill also had slower brain shrinkage — particularly in the hippocampus, which controls memory and thinking, the atrophy was about 18% less than those taking the placebo. —Melissa Rudy, FOXNews.com, 30 Oct. 2025

In the hippocampus, for example, participants who got ALZ-801 experienced about 18% less atrophy than those who got a placebo. —Jon Hamilton, NPR, 29 Oct. 2025

Word History

Etymology

New Latin, from Greek hippokampos seahorse, from hippos horse + kampos sea monster — more at equine

First Known Use

1695, in the meaning defined above

Rhymes for hippocampus

• campus
• grampus

Medical Definition

hippocampus

noun

hip·​po·​cam·​pus ˌhip-ə-ˈkam-pəs 

plural hippocampi -ˌpī  -(ˌ)pē 

: a curved elongated ridge that is an important part of the limbic system, extends over the floor of the descending horn of each lateral ventricle of the brain, consists of gray matter covered on the ventricular surface with white matter, and is involved in forming, storing, and processing memory see pes hippocampi