a. [ Gr. &unr_; of one tribe, fr. mo`nos single + &unr_; clan. ] (Biol.) Of or pertaining to a single family or stock, or to development from a single common parent form; -- opposed to polyphyletic; as, monophyletic origin. [ 1913 Webster ]

a. [ Poly- + Gr. &unr_; clan. ] (Biol.) Pertaining to, or characterized by, descent from more than one root form, or from many different root forms; polygenetic; -- opposed to monophyletic. [ 1913 Webster ]