vestigial ves·tig·i·al (vě-stĭj'ē-əl, -stĭj'əl)
Occurring or persisting as a rudimentary or degenerate structure.
|vestigial (vě-stĭj'ē-əl) Pronunciation Key
Relating to a body part that has become small and lost its use because of evolutionary change. Whales, for example, have small bones located in the muscles of their body walls that are vestigial bones of hips and hind limbs.