ὕδρος
From LSJ
ἐπέμψατε ἀγγέλους τοῖς ἀλλήλοις ὥστε ἔγνωτε τὸν κίνδυνον → you sent messengers to one another so that you knew the danger
English (LSJ)
ὁ, (ὕδωρ)
A water-snake, Coluber natrix, Il.2.723, Hdt.2.76, Arist.HA487a23, 508b1; λευκὸς ὡς ὕδρου γαστήρ Call.Iamb.1.218 ( = εἶδος δράκοντος, Sch. in mg.). II a small water-animal, = φαλάγγιον or σαῦρος, Artem.4.56. III the constellation Hydra, Eudox. ap. Hipparch.2.2.13. (Cf. Skt. udrás, OE. oter 'otter'.)