Oatmeal is made of
oat groats (i.e. grains) that have either been ground, crushed,
steel-cut, or
rolled. Ground oats are also called "white oats". Steel-cut oats are known as "coarse oatmeal" or "Irish oatmeal" or "pinhead oats". The term "oatmeal" is also used in the U.S. and parts of Canada to mean oat
porridge.
Quaker oats, with its distinctive Quaker man logo, is a brand commonly associated with oatmeal.