φράγμα

A. fence, breast-work, screen, Hdt. 8.52, Pl. Plt. 279d (pl.); protection, τοῖς ἕλκεσι Gal. 15.343; boom placed in a harbour, Aen.Tact. 37.8.

b. contrivance for catching fish, Str. 17.2.5.

2. generally, defence, means of defence, μετώπων φράγματα, of a stag's horns, AP 6.110 (Leon. or Mnasalc.); of the ink of the sepia, Arist. PA 679a6; of the eyelids, Id. de An. 421b29.