Which greek word refers to water?

Ελληνική (Greek)

n. - νερό, (μτφ.) ιριδισμός (υφάσματος κ.λπ.)

v. - αρδεύω, ποτίζω, βρέχω, καταβρέχω, διαβρέχω, νερώνω

adj. - υδάτινος, του νερού

pref. - υδάτινος I believe it could be aqua or hydra, but i don't know much Latin, so I tried my best.