Definition of water dragon:
(n) :
Any of various agamid lizards of eastern Asia and Australasia, including the genera Physignathus, Intellagama, and Tropicagama, all of subfamily Amphibolurinae.
(n) :
A knucker, a lizard of English folklore.
(n) :
A marsh marigold (Caltha palustris)
(n) :
The lizard's tail plant (Saururus cernuus)