Lewis & Short

plangor, ōris, m. [plango], a striking, beating, attended with noise.

  1. I. In gen. (poet.): (undae) leni resonant plangore cachinni, Cat. 64, 272: feminis, Auct. Her. 3, 15; Ov. M. 3, 498.
  2. II. In partic., a beating the breast or face in token of grief; loud mourning, wailing, lamentation (class.): plangore et lamentatione complere forum, Cic. Or. 38, 131: feminei, Verg. A. 2, 487: dare plangorem, to make, Ov. M. 14, 421: percutit claro plangore lacertos, id. ib 4, 138: caesis plangore lacertis, id. ib. 6, 532.