Definition of: grain

(grān) noun
1. Any very small, hard mass: a grain of sand; especially, a seed resembling this; a kernel.
2. Any of the common cereals; specifically, the seed or fruit of any cereal, collectively, as wheat, oats, rye, barley, etc.
3. A minute particle.
4. A unit of weight, equal to 1/20 of a scruple apothecary: 1 oz. apothecary or troy contains 480 grains; 1 oz. avoirdupois contains 437.5 grains.
5. A unit of weight for pearls, equal to 1/4 of a metric carat or 50 milligrams.
6. The arrangement of the particles of a body of granular texture; hence, degree of coarseness, roughness, fineness of surface, direction or set of fibers, etc.: the grain of wood or leather.
7. The innate quality or character of a thing.
8. The cochineal insect, originally mistaken for a seed; hence, a red or purple dye, or any fast color.
9. plural Refuse grain or malt after brewing.
10. Natural disposition; temper. See synonyms under PARTICLE, TEMPER
—in grain or in the grain
1. Set; fixed: said of dye.
2. Figuratively, innate; deeply rooted; ineradicable.
—v.t.
1. To form into grains; granulate.
2. To paint or stain in imitation of the grain of wood, marble, etc.
3. In leather-making: a To scrape off hair from with a grainer. b To soften or raise the grain or pattern of.
—v.i.
4. To form grains. [Fusion of OF grain a seed and graine seed, grain, both <L granum a seed]