fornix

noun

for·​nix ˈfȯr-niks 

plural fornices ˈfȯr-nə-ˌsēz 

: an anatomical arch or fold: such as

a

: the junction where the conjunctiva lining the eyelid meets the conjunctiva overlying the sclera

b

: a body of nerve fibers lying beneath the corpus callosum with which they are continuous posteriorly and serving to integrate the hippocampus with other parts of the brain

c

: the vaulted upper part of the vagina surrounding the uterine cervix

Examples of fornix in a Sentence

Recent Examples on the Web

For example, try wearing a butt plug while stimulating your anterior fornix or A-spot, which is deeper than the G-spot and is located between the cervix and vaginal wall. —Amanda Chatel, Glamour, 9 Jan. 2025

Typically made from medical-grade silicone, menstrual discs are held in place by their rim in the vaginal fornix. —goodhousekeeping.com, 16 May 2023

At the age of 8, he was referred for an MRI scan, which revealed severe atrophy of the hippocampus, and the related structures the fornix and the mammilary bodies, on both sides of the brain. —Neuroskeptic, Discover Magazine, 13 Nov. 2010

The fornix is important in remembering personal events and concepts. —Wissam Deeb, Discover Magazine, 23 Sep. 2019

In Alzheimer’s disease, the memory circuits in the brain, which include a notable structure called the fornix, are affected. —Wissam Deeb, Discover Magazine, 23 Sep. 2019

The fornix, a tiny part of the brain, may hold some clues to memory loss. —Wissam Deeb, Discover Magazine, 23 Sep. 2019

The hypothalamus is involved in regulating appetite, not memory - but the fornix, a nerve bundle that passes through that area, is. —Neuroskeptic, Discover Magazine, 9 Aug. 2010

While the menstrual cup sits in the vaginal canal where a tampon also sits, menstrual discs sit at the vaginal fornix, which is deeper into the vaginal canal. —Suzannah Weiss, Glamour, 6 July 2020

Word History

Etymology

borrowed from New Latin, going back to Latin, "arch, vault," perhaps a derivative from the same base as fornāx, furnāx "furnace, oven, kiln" — more at furnace

Note: Alternatively, fornix has been taken as one outcome of an Indo-European verbal base *d^hu̯er(h₁)- "diverge"—see discussion at Nomina im Indogermanischen Lexikon (Heidelberg, 2008), p. 132.

First Known Use

1681, in the meaning defined above

Medical Definition

fornix

noun

for·​nix ˈfȯr-niks 

plural fornices -nə-ˌsēz 

: an anatomical arch or fold: as

a

: the vault of the cranium

b

: the junction where the conjunctiva lining the eyelid meets the conjunctiva overlying the sclera

c

: a body of nerve fibers lying beneath the corpus callosum with which they are continuous posteriorly and serving to integrate the hippocampus with other parts of the brain

d

: the vaulted upper part of the vagina surrounding the uterine cervix

e

: the fundus of the stomach

f

: the vault of the pharynx