(in humans) 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
Word origin
C18: from Latin os sacrum holy bone, because it was used in sacrifices, from sacer holy
sacrum in American English
(ˈseɪkrəm; ˈsækrəm)
nounWord forms: pluralˈsacra (ˈseɪkrə; ˈseɪrə) or ˈsacrums
a thick, triangular bone situated near the lower end of the spinal column, where it joins both innominate bones to form the dorsal part of the pelvis: it is formed in humans of five fused vertebrae
Word origin
ModL < LL (os) sacrum, lit., sacred (bone), transl. of Gr hieron osteon < hieron, sacred, ? last (< hieros: see hiero-) + osteon: see ossify