syn·​sacrum | \ "+\

Definition of synsacrum

: a solidly fused series of vertebrae in the pelvic region in birds, dinosaurs, and pterosaurs comprising usually the last rib-bearing or thoracic vertebra, the two sacral vertebrae, and a varying number of caudal vertebrae — compare sacrum

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History and Etymology for synsacrum

New Latin, from syn- + sacrum

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