ischium

noun

is·​chi·​um ˈi-skē-əm 

plural ischia ˈi-skē-ə 

: the lower and posterior of the three principal bones composing either half of the pelvis

ischial

ˈi-skē-əl 

adjective

Examples of ischium in a Sentence

Recent Examples on the Web

The skeleton is nearly 80 percent complete, with its pelvic bones, pubis, hind limbs and the ischium all present from the evacuation. —Dana Givens, Robb Report, 5 Dec. 2022

The bones also included a right thighbone (femur) and hipbone (ischium), a right arm, and part of a lower right jaw and a few teeth. —Kiona N. Smith, Ars Technica, 10 Apr. 2020

Ribs, back and lower hips If all goes to plan, this second week will also see Sue lose its chest ribs, neck and chest backbones, and pubis and ischium (the lower hip bones). —Steve Johnson and Phil Geib, chicagotribune.com, 3 Feb. 2018

The ornithischians were a vegan bunch — both their ischium and pubis pelvic bones pointed backwards, creating more room in the gut area to process all that vegetation. —Gemma Tarlach, Discover Magazine, 1 Nov. 2017

Word History

Etymology

Latin, hip joint, from Greek ischion

First Known Use

1646, in the meaning defined above

Kids Definition

ischium

noun

is·​chi·​um ˈis-kē-əm 

plural ischia

-kē-ə

: the one of the three bones making up each side of the pelvis that is lowermost and in back

Medical Definition

ischium

noun

is·​chi·​um ˈis-kē-əm 

plural ischia -ə 

: the dorsal and posterior of the three principal bones composing either half of the pelvis consisting in humans of a thick portion, a large rough eminence on which the body rests when sitting, and a forwardly directed ramus which joins that of the pubis