Learner's definition of GRAIN
1 a [noncount] : the seeds of plants (such as wheat, corn, and rice) that are used for foodalso [count] : a single seed of wheat, corn, rice, etc. b : a plant that produces grain
2 a : a small, hard piece of something b : a very small amount of something
— see also take (something) with a grain of salt at 1salt
3 a : the way the lines or fibers in something (such as wood) are arranged— usually singular b : the way that the surface of something feels when it is touched— usually singular 4 [count] : a unit of weight equal to 0.0648 grams
against the grain
◊ To be/go against the grain is to be different or to act in a way that is different from what is normal or usual.
◊ If something goes against your grain, it does not seem right or natural to you.