sacrum
Americannoun
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sacra
plural
noun
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(in man) the large wedge-shaped bone, consisting of five fused vertebrae, in the lower part of the back
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the corresponding part in some other vertebrates
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sacra
plural
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A triangular bone at the base of the spine, above the coccyx (tailbone), that forms the rear section of the pelvis. In humans it is made up of five vertebrae that fuse together by adulthood.
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See more at skeleton
Other Word Forms
Noun Inflected Forms
Etymology
Origin of sacrum
1745–55; < Late Latin ( os ) sacrum holy (bone), translation of Greek hieròn ostéon
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Explanation
The sacrum is the large, triangle-shaped bone at the base of the spine. Many, though not all, animals with a backbone also have a sacrum. In humans, the sacrum sits wedged between the two hip bones, connecting the lowest vertebra of the spine with the tailbone or coccyx. A man's sacrum is slightly different from a woman's: it's taller and narrower, with a larger curve. The word comes from the Latin phrase os sacrum, or "sacred bone," and it was named this way because the large sacrum of animals was often a part of ritual sacrifices in ancient times.
Vocabulary lists containing sacrum
Human Anatomy and Physiology - High School
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sacr, sanc, secr
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
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Deputies with the Humboldt County Sheriff’s Office identified it as a human sacrum, the triangular bone at the base of the spine, and submitted it to a state Department of Justice system of DNA samples.
From Los Angeles Times ● Sep. 21, 2026
The sacrum is a group of vertebrae connected to the pelvis and forms part of the animal's lower spine.
From Science Daily ● Aug. 14, 2026
The concept of a Christian “holy war”—a war conferring spiritual benefits—originates in medieval Latin Christianity, with its crusader theology of bellum sacrum.
From The Wall Street Journal ● Jun. 19, 2026
Woods said his sacrum had to be put back in place.
From Seattle Times ● May 15, 2024
The Iliac Bone.—The iliac or coxal bone, is a paired or non-symmetrical bone, united below to its fellow of the opposite side, while it is separated from it above by the sacrum.
From Artistic Anatomy of Animals by ?douard Cuyer
With a practised flick, he cuts a strip of bark from the trunk of one of the Boswellia sacra trees.
From BBC ● Feb. 9, 2010
Most of the Boswellia sacra trees grow on public land, but custom dictates that each forest is given to one of the local families to farm, and Wadi Dawkah is his turf.
From BBC ● Feb. 9, 2010
Warm winters and showery summers are the perfect conditions for the Boswellia sacra tree to produce the sap called frankincense.
From BBC ● Feb. 9, 2010
The leading idea in both cases remains the same; it is the fatal curse which attaches to the gold or, which is the same in a moral sense, to the desire for gold—auri sacra fames.
From A Selection from the Poems of William Morris by William Morris
The auri sacra fames had formed a league with a fanatical sectional party.
From The Women of the Confederacy by J. L. Underwood
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