coccyx
Americannoun
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a small triangular bone forming the lower extremity of the spinal column in humans, consisting of four ankylosed rudimentary vertebrae.
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a corresponding part in certain animals.
noun
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A small triangular bone at the base of the spine in humans and apes. It is composed of several fused vertebrae.
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Also called tailbone
Other Word Forms
Etymology
Origin of coccyx
1605–15; < New Latin < Greek kókkyx cuckoo, from its resemblance to a cuckoo's beak
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Vocabulary lists containing coccyx
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.
The boy was fifteen, skinny, almost malnourished, so that the hip bones and coccyx stood out sharply.
From The Wall Street Journal • Nov. 11, 2025
Following this evolutionary split, the group of apes that includes present-day humans evolved the formation of fewer tail vertebrae, giving rise to the coccyx, or tailbone.
From Science Daily • Feb. 28, 2024
The adult vertebral column comprises 26 bones: the 24 vertebrae, the sacrum, and the coccyx bones.
From Textbooks • Jun. 9, 2022
The spinal column is composed of the seven cervical vertebrae, the nine thoracic vertebra, the four lumbar vertebrae, the sacrum, and the coccyx.
From Textbooks • Jan. 1, 2015
In animals the sacrum and the coccyx, as a matter of fact, clearly continue the superior border of the skeleton of the trunk; hence we study them with the vertebral column.
From Artistic Anatomy of Animals by Cuyer, ?douard
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
