Grain  —n. 1 fruit or seed of a cereal. 2 (collect.) Wheat or any allied grass used as food; corn. 3 small hard particle of salt, sand, etc. 4 unit of weight, 0.0648 gram. 5 smallest possible quantity (not a grain of truth in it). 6 roughness of surface. 7 texture of skin, wood, stone, etc. 8 a pattern of lines of fibre in wood or paper. B lamination in stone etc. —v. 1 paint in imitation of the grain of wood etc. 2 give a granular surface to. 3 form into grains.  against the grain contrary to one's natural inclination or feeling.  grainy adj. (-ier, -iest). [latin granum]