Lewis & Short

1. oscillum, i, n. dim. [1. os; lit. little mouth; hence],

  1. I. A little cavity in the middle of leguminous fruits, where the germ sprouts forth: oscilla lupinorum, Col. 2, 10, 3.
  2. * II. A little image of the face, a little mask of Bacchus, hung from trees, so as to be easily moved by the wind: tibique (Bacche) Oscilla ex altā suspendunt mollia pinu, Verg. G. 2, 389; cf. Serv. ad loc.; Macr. S. 1, 7; 11.