Lewis & Short

planctus, ūs, m. [plango].

  1. I. In gen., a striking or beating accompanied by a loud noise, a banging, rustling, roaring (postAug. and mostly poet.): unum omnes incessere planctibus, of the flappings of the Harpies’ wings, Val. Fl. 4, 494: tremuit perterritus aether Planctibus insolitis, Petr. 136: planctus illisae cautibus undae, of the roaring of the waves, Luc. 6, 690.
  2. II. In partic., a beating of the breast, arms, and face in mourning; a wailing, lamentation, lament (syn.: plangor, lamentum, ploratus): clamor barbaro ululatu planctuque permixtus, Curt. 3, 12, 3: lamentis et planctibus tota regia personabat, id. 10, 5, 7; Sen. Cons. ad Marc. 6, 2; Val. Max. 2, 6, 7; Sen. Troad. 92: pectora illiso sonent Contusa planctu, id. Thyest. 1045: verberabam aegrum planctibus pectus, Petr. 81; Luc. 2, 23: gemitus ac planctus, groans and lamentations, Tac. A. 1, 41; Flor. 4, 1 med.: et factus est planctus magnus in Israel, Vulg. 1 Macc. 1, 26 et saep.