Pygostyles

Part of speech: noun

Definitions

1. The fused terminal vertebrae found in certain birds supporting tail feathers ; a structure serving as the foundation for tail feather attachment ; the skeletal segment at the rear end of a bird's spine aiding tail mobility
2. A bone complex at the bird's posterior composed of united vertebrae facilitating tail feather anchorage ; the endpoint of the spinal column in birds providing support for tail plumage ; the fused vertebral mass allowing movement and stability of the tail feathers
3. The anatomical formation consisting of merged caudal vertebrae in birds that supports tail feathers ; the spine's final section adapted for tail feather placement and control ; the rigid vertebral cluster at the bird's tail base instrumental in tail function

Etymology: "Pygostyles" is the plural of "pygostyle", a term for the fused bone at the end of a bird's tail. The word is built from two parts: "pygo-", from Ancient Greek "pygē" meaning "rump", and "style", from Ancient Greek "stūlos" meaning "column" or "pillar". Put together, the name describes the bone's shape: a rigid little pillar of vertebrae standing at the rear of the body, which supports the tail feathers. The "style" element is an ordinary English word in its own right, but in scientific coinages like this one it carries the sense of a slender rod or post. The "pygo-" prefix is the more specialised part, and it appears in other anatomical terms built on the same Greek root for the buttocks or rump. Because the word is a modern technical coinage from classical parts, it was not used by the ancient Greeks, who had no concept of a bird's fused tail bone as a named structure.

Synonyms: bird tailbones