• synonyms


[sak-ruh m, sey-kruh m]
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noun, plural sac·ra [sak-ruh, sey-kruh] /ˈsæk rə, ˈseɪ krə/. Anatomy.
  1. 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.
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Origin of sacrum

1745–55; < Late Latin (os) sacrum holy (bone), translation of Greek hieròn ostéon
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Related Words for sacrum

backside, back, duff, buttocks, butt, behind, seat, beam, tail, tush, can, bum, keister, moon, fanny, rear, prat, breech, sacrum, croup

Examples from the Web for sacrum

Historical Examples of sacrum

  • Distance from acetabular axis to anterior end of sacrum 30 mm.

    Extinct Birds

    Walter Rothschild

  • The straightness of the sacrum will also be a guide in other cases.

  • The ilia are not connected with the sacrum by ossified sacral ribs.

    The Vertebrate Skeleton

    Sidney H. Reynolds

  • The sacrum is formed by a number of caudal and dorsal vertebr.

    Reptiles and Birds

    Louis Figuier

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


    Philip Henry Gosse

British Dictionary definitions for sacrum


noun plural -cra (-krə)
  1. (in man) the large wedge-shaped bone, consisting of five fused vertebrae, in the lower part of the back
  2. the corresponding part in some other vertebrates
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Word Origin for sacrum

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

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."

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Online Etymology Dictionary, © 2010 Douglas Harper

sacrum in Medicine


(sākrəm, săkrəm)
n. pl. sa•cra (krə, săk)
  1. 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.
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The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

sacrum in Science


[sākrəm, săkrəm]
Plural sacra
  1. 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.
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The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.