Grits are a form of ground corn, usually served with the consistency of porridge. More on it here: https://en.wikipedia.org/wiki/Grits
Some places here in the Midwest serve them as well. I know some people - like DH - eat theirs with butter. For me, I have to put something sweet (like apple butter) in mine if I really have to eat them. I'm not much of a fan of them.