Definitions for water oak
Random House Webster's College Dictionary
an oak, Quercus nigra, of the southern U.S., growing chiefly along streams and swamps.
any of several other American oaks of similar habit.
Origin of water oak:
water oak, possum oak, Quercus nigra(noun)
relatively tall deciduous water oak of southeastern United States often cultivated as a shade tree; thrives in wet soil
A type of hard oak tree, Quercus nigra, of the southern US.