synsacrum

[ sin-sak-ruhm, -sey-kruhm ]

noun

, Ornithology.

, plural syn·sac·ra [sin-, sak, -r, uh, -, sey, -kr, uh].

1. a dorsal ridge of bone in the pelvic region of birds, formed by the fusion of certain thoracic, lumbar, sacral, and caudal vertebrae.

Other Words From

• syn·sacral adjective
• presyn·sacral adjective

Word History and Origins

Origin of synsacrum¹

First recorded in 1900–05; syn- + sacrum