a fragrant, white, crystalline substance, (CHO)(OH)CHCHO, produced from the vanilla bean or made synthetically: used for flavoring, in the manufacture of perfumes, etc.
See vanillin in American Heritage Dictionary 4
noun
A white or yellowish crystalline compound, C8H8O3, found in vanilla beans and certain balsams and resins and used in perfumes, flavorings, and pharmaceuticals.