I tend to agree with bns ... I wouldn't call oil "wet" either ... it's not an intuitive use of the word. Maybe a better definition would be:

water = liquid H2O
is wet = contains liquid H2O

Then on this definition, the statement "water is wet" makes more sense.

Although I might note that English is a pre-scientific language, really based more on perception than scientific concepts. Defining it this way possibly changes the meaning of the words.