Many things that are called nuts actually aren't by the strict botanical definition. For example: almonds, Brazil nuts, cashews, macadamias, peanuts, pecans, pine nuts, pistachios and walnuts are all...
1.) A type of seed. It has a hard outside, and the seed is on the inside. Some are edible, like cashews and peanuts. Other examples include walnuts and acorns.
2.) A vulgar term for one of the male...
Not in Grape Nut Flakes, but I'm not too sure about actual Grape Nuts. I would go to the store and check the ingredients on the nutrition label on the side of the box. That would probably tell you.