plica, n. [LL., a fold, fr. L. plicare to fold. See Ply, v.].
A disease of the hair (Plica polonica), in which it becomes twisted and matted together. The disease is of Polish origin, and is hence called also Polish plait. Dunglison. [1913 Webster]
A diseased state in plants in which there is an excessive development of small entangled twigs, instead of ordinary branches. [1913 Webster]