Oatmeal refers to a preparation of oats that have been dehusked, steamed and flattened, or else a coarse flour made of hulled oat grains (groats) that have either been milled (ground) or steel-cut. Ground oats are also called “white oats”. Steel-cut oats are known as “coarse oatmeal”, “Irish oatmeal” or “pinhead oats”. Rolled oats were traditionally thick “old-fashioned oats”, but can be made thinner or smaller, and may be categorized as “quick” or “instant”, depending on the cooking time, which is shortened by the size of the oats and precooking.
The term oatmeal is used to describe a common oat porridge made from ground, steel-cut, or rolled oats. Some commercial packages display other ingredients, such as sugar, salt, flavorings, thickeners, vitamins or minerals, while highlighting quick (“instant”) cooking and separately packaged individual portions for convenience.