sacrum

Từ điển WordNet v3.1 - WordNet Dictionary

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
• Derivationally related forms:
sacral
• Hypernyms:
bone, os
• Part Holonyms:
pelvis, pelvic girdle, pelvic arch, hip
• Part Meronyms:
sacral vertebra