The grain is known to be the part of the plant that is small and usually edible—most of the grains that you will find some from grassy crops such as rice. Seeds, on the other hand, will usually be found inside the fruit of a plant.
They may be covered first by a seed coat, which means that the seed will be harder than a grain. A seed will have the ability to become another plant while the grain will not have this ability.
Another difference is that the seed is usually produced because of the sexual reproduction of plants or sometimes just one plant. The grain can be a type of seed, or it can also be a fruit which, like mentioned earlier, will come from grassy plants.