sacrum

/ˈseɪkrəm/

/ˈseɪkrəm/

Other forms: sacra

The sacrum is the large, triangle-shaped bone at the base of the spine. Many, though not all, animals with a backbone also have a sacrum.

In humans, the sacrum sits wedged between the two hip bones, connecting the lowest vertebra of the spine with the tailbone or coccyx. A man's sacrum is slightly different from a woman's: it's taller and narrower, with a larger curve. The word comes from the Latin phrase os sacrum, or "sacred bone," and it was named this way because the large sacrum of animals was often a part of ritual sacrifices in ancient times.

Definitions of sacrum

1. noun

   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
   type of:

   bone, os

   rigid connective tissue that makes up the skeleton of vertebrates