vestigial /vɛˈstɪd͡ʒɪəl/adjective 3noun 1forms 1 adjective3 •Of or pertaining to a vestige or remnant; like a trace from the past. •Not fully developed in mature animals. •Of a vestigial structure; that has lost all or most of its original function in the course of evolution. noun1 •A small, degenerate, or imperfectly developed part or organ which has been more fully developed in some past generation. formsvestigials