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[sak-ruh m, sey-kruh m] /ˈsæk rəm, ˈseɪ krəm/
noun, plural sacra
[sak-ruh, sey-kruh] /ˈsæk rə, ˈseɪ krə/ (Show IPA).
a bone resulting from the fusion of two or more vertebrae between the lumbar and the coccygeal regions, in humans being composed usually of five fused vertebrae and forming the posterior wall of the pelvis.
Origin of sacrum
1745-55; < Late Latin (os) sacrum holy (bone), translation of Greek hieròn ostéon Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2017.
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Examples from the Web for sacrum
Historical Examples
  • The ilia are not connected with the sacrum by ossified sacral ribs.

    The Vertebrate Skeleton Sidney H. Reynolds
  • Distance from acetabular axis to anterior end of sacrum 30 mm.

    Extinct Birds Walter Rothschild
  • The former is one of the amphiarthroses or half-joints by which the sacrum is bound to the ilium.

  • The ossification of the sacrum also has reached its culminating point.

    Omphalos Philip Henry Gosse
  • The bone immediately below the sacrum, called the coccyx, is essentially the representative of the tail in man.

    Degeneracy Eugene S. Talbot
  • The structure so formed may be named the notarium to distinguish it from the sacrum.

    Dragons of the Air H. G. Seeley
  • Each half is firmly united to its fellow in a ventral symphysis behind, and is in front expanded and united to the sacrum.

    The Vertebrate Skeleton Sidney H. Reynolds
  • They are united to the sacrum behind and joined to each other in front.

    A Practical Physiology Albert F. Blaisdell
  • But the joints of the backbone in front of the sacrum receive their air from the cervical air sac.

    Dragons of the Air H. G. Seeley
  • Also note how much longer and more solid the sacrum (with its attached bone, called the coccyx) is in the male pelvis.

    Woman William J. Robinson
British Dictionary definitions for sacrum


/ˈseɪkrəm; ˈsækrəm/
noun (pl) -cra (-krə)
(in man) the large wedge-shaped bone, consisting of five fused vertebrae, in the lower part of the back
the corresponding part in some other vertebrates
Word Origin
C18: from Latin os sacrum holy bone, because it was used in sacrifices, from sacer holy
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
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Word Origin and History for sacrum

bone at the base of the spine, 1753, from Late Latin os sacrum "sacred bone," from Latin os "bone" (see osseous) + sacrum, neuter of sacer "sacred" (see sacred). Said to be so called because the bone was the part of animals that was offered in sacrifices. Translation of Greek hieron osteon. Greek hieros also can mean "strong," and some sources suggest the Latin is a mistranslation of Galen, who was calling it "the strong bone."

Online Etymology Dictionary, © 2010 Douglas Harper
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sacrum in Medicine

sacrum sa·crum (sā'krəm, sāk'rəm)
n. pl. sa·cra (sā'krə, sāk'rə)
The triangular segment of the spinal column that forms part of the pelvis and closes in the pelvic girdle posteriorly, is formed between the ages of 16 and 25 by the fusion of five originally separate sacral vertebrae, and articulates with the last lumbar vertebra, the coccyx, and the hipbone on either side.

The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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sacrum in Science
  (sā'krəm, sāk'rəm)   

Plural sacra
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. See more at skeleton.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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