ischium

noun

is·​chi·​um ˈi-skē-əm How to pronounce ischium (audio)
plural ischia ˈi-skē-ə How to pronounce ischium (audio)
: the lower and posterior of the three principal bones composing either half of the pelvis
ischial
ˈi-skē-əl How to pronounce ischium (audio)
adjective

Examples of ischium in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
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 The animal — which, by the way, is known from several specimens — had a pelvic girdle with rear-pointing pubis and ischium, like the ornithischians. — Gemma Tarlach, Discover Magazine, 16 Aug. 2017

Word History

Etymology

Latin, hip joint, from Greek ischion

First Known Use

1646, in the meaning defined above

Time Traveler
The first known use of ischium was in 1646

Browse Nearby Words

ischiopodite
ischium
Ischyodus
See all Nearby Words

Cite this Entry

“Ischium.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/ischium. Accessed 18 Apr. 2025.

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Kids Definition

ischium

noun
is·​chi·​um ˈis-kē-əm How to pronounce ischium (audio)
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 How to pronounce ischium (audio)
plural ischia -ə How to pronounce ischium (audio)
: 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

More from Merriam-Webster on ischium

Britannica.com: Encyclopedia article about ischium

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