also called pinhead oats, coarse oatmeal (UK), or Irish oatmeal are groats (the inner kernel with the inedible hull removed) of whole oats which have been chopped into two or three pinhead-sized pieces (hence the names; "steel-cut" comes from the steel blades).

A type of lightly processed whole-grain food. Traditionally, they are made from oat groats that have been de-husked and steamed, before being rolled into flat flakes under heavy rollers and then stabilized by being lightly toasted.

Quick oats or quick-cooking oats are rolled oats that go through further processing to decrease cooking time. They’re partially cooked by steaming and then rolled even thinner than old-fashioned oats. They cook within a few minutes, have a mild flavor and soft, mushy texture. Quick oats are not the same as instant, packaged oats that sometimes contain other ingredients like skim milk powder, sugar and flavoring.