痕こん跡せき器き官かん

noun

vestigial organ; rudimentary organ

A biological term for an organ that has lost most or all of its original function through evolution.

• ヒトの尾び骨こつは痕こん跡せき器き官かんの一いち例れいだ。

  The human coccyx is an example of a vestigial organ.