ὕδρα

English (LSJ)

Ion. ὕδρη, ἡ, (cf. ὕδωρ)

   A water-serpent, but esp. of the Lernaean hydra, Hes.Th.313, S.Tr.574,836 (lyr.), 1094; Ὕδραν τέμνειν, prov. of labour in vain, because two heads sprang up for every one which was cut off, Pl.R.426e: pl., but still with reference to the Lernaean hydra, E.Heracl.950, Ph.[1136]: prov., ὕδρης ποικιλώτερος Herod.3.89 (ἐπὶ τῶν δολερῶν Diogenian.7.69).    II name of a constellation, = ὕδρος 111, Arat.444, etc.