Sacrum n. : That part of the vertebral column which is directly connected with, or forms a part of, the pelvis.

Example:
I broke my Sacrum in 2008. How long does it take to heal and what can i do for pain?

Taxonomy
sacrum, bone, os sacrum, free encyclopedia, coccyx, Female Pelvis, triangular bone, base of the sacrum, sagittal section, ala of sacrum, sacral canal, spinous processes, foramina, hip bone, pelvis, lumbar vertebra, vertebrae, obliquely.

Defination from the web:
sacrum, which is broad and expanded, is directed upward and forward. The apex (apex oss. ... The sacrum is noticeably sexually dimorphic (differently-shaped in males and females). In the female the sacrum is shorter and wider than in the male; the lower half forms a ...