sacrum

sa·crum

noun \ˈsak-rəm, ˈsā-krəm\

plural sa·cra \ˈsak-rə, ˈsā-krə\

Definition of SACRUM

: the part of the spinal column that is directly connected with or forms a part of the pelvis by articulation with the ilia and that in humans forms the dorsal wall of the pelvis and consists of five fused vertebrae diminishing in size to the apex at the lower end which bears the coccyx

Illustration of SACRUM