WordReference Random House Unabridged Dictionary of American English © 2025
syn•sac•rum
(sin sak′rəm, -sā′krəm),USA pronunciation n., pl. -sac•ra (-sak′rə, -sā′krə).USA pronunciation [Ornith.]
syn•sa′cral, adj.
- Birdsa dorsal ridge of bone in the pelvic region of birds, formed by the fusion of certain thoracic, lumbar, sacral, and caudal vertebrae.
- syn- + sacrum 1900–05