Word before oil or water
I believe the answer is:
mineral
'word before oil or water' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for mineral that I've seen before include "ore, possibly" , "Neither animal nor vegetable" , "Type of spring water" , "Made from inorganic matter" , "Gypsum or magnesium, say" .)