sacrum /ˈseɪkrəm 
, ˈsakrəm / ▸ noun (plural sacra /ˈseɪkrə /) (plural or sacrums)
Anatomy a triangular bone in the lower back formed from fused vertebrae and situated between the two hip bones of the pelvis. – ORIGIN mid 18th century: from Latin os sacrum, translation of Greek hieron osteon ‘sacred bone’ (from the belief that the soul resides in it).
EnglishOxford Dictionary of English
