ὕδνης
From LSJ
ἐς δὲ τὰ ἔσχατα νουσήματα αἱ ἔσχαται θεραπεῖαι ἐς ἀκριβείην, κράτισται → for extreme diseases, extreme methods of cure, as to restriction, are most suitable (Corpus Hippocraticum, Aphorisms 1.6.2)
English (LSJ)
A = εἰδώς, ἔμπειρος (cf. ὕδης), Hsch. II ὕδναι, = ἔγγονοι, σύντροφοι, Id. (perhaps as root of Ἁλοσ-ύδνη, Ὑδατοσ-ύδνη).
Greek (Liddell-Scott)
ὕδνης: -ου, ὁ, = εἰδώς, ἔμπειρος (πρβλ. ὕδης), Ἡσύχ. ΙΙ. = ἔγγονος, σύντροφος, παρὰ τῷ αὐτῷ (ἴσως ὡς ῥίζα τοῦ Ἁλοσύδνη, Ὑδατοσύδνη).
German (Pape)
1 = ὕδης, ἔμπειρος, εἰδώς, VLL.
2 ὁ, eigtl. wässerig, naß, dah. nahrhaft, nährend, auch pass., genährt, in VLL, die davon Ἁλοσύδνη ableiten.