sacrum(redirected from Os sacrum)
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Related to Os sacrum: sacral, sacral bone
n. pl. sa·cra (sā′krə, săk′rə)
A triangular bone made up of five fused vertebrae and forming the posterior section of the pelvis.
[New Latin, from Late Latin (os) sacrum, sacred (bone), sacrum (translation of Greek hieron (osteon), sacred (bone), so called from the use of the sacrum and coccyx of sacrificed animals in divination ), neuter of Latin sacer, sacred, holy; see sacred.]
Word History: The human sacrum consists of five fused vertebrae, to which the coccyx or tailbone—the vestigial remnant of a tail—is attached. In Latin, this large bone was called os sacrum, literally "holy bone." (Os means "bone" in Latin, and sacrum is a form of the Latin adjective sacer, "holy," which is also the source of a number of other English words like sacred, sacrifice, and sacrilege.) The Latin term for the bone is in turn a translation of its Greek name, hieron osteon. (Hieron is a form of the Greek adjective hieros, "holy," while osteon means "bone" in Greek.) In ancient Greek animal sacrifices, certain portions of the victim were reserved for the gods, and among these was the sacrum with the tail still attached. After the gods' portions were placed in the sacrificial fire, a seer or diviner would often observe how the tail curled and sputtered in the flames, and he would interpret these signs as favorable or unfavorable. Greek representations of animal sacrifices on painted ceramics often show the tail curling in the fire and thus revealing the will of the gods.
n, pl -cra (-krə)
1. (Anatomy) (in man) the large wedge-shaped bone, consisting of five fused vertebrae, in the lower part of the back
2. (Zoology) the corresponding part in some other vertebrates
[C18: from Latin os sacrum holy bone, because it was used in sacrifices, from sacer holy]
sac•rum(ˈsæk rəm, ˈseɪ krəm)
n., pl. sac•ra (ˈsæk rə, ˈseɪ krə)
a bone between the lumbar vertebrae and tail vertebrae, composed of five fused vertebrae that form the posterior pelvic wall.
[1745–55; < Late Latin (os) sacrum holy (bone)]
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.
Five fused vertebrae joined to the two hip bones.
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|Noun||1.||sacrum - wedge-shaped bone consisting of five fused vertebrae forming the posterior part of the pelvis; its base connects with the lowest lumbar vertebra and its tip with the coccyx|
sacral vertebra - one of 5 vertebrae in the human spine that fuse in the adult to form the sacrum