Plica meaning : A fold or crease, especially of skin or other tissue. Polish plait, plica polonica, or plica neuropatica: a disease of the hair in which it becomes twisted and matted together. A diseased state in plants in which there is an excessive development of small entangled twigs, instead of ordinary branches. The bend of the wing of a bird. A neume, in the form of a tail at the end of a ligature, indicating an additional note.