Sacrum

n.

1.

(Anat.) That part of the vertebral column which is directly connected with, or forms a part of, the pelvis.

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

bone, hip, os, pelvic arch, pelvic girdle, pelvis, sacral vertebra