Oat flakes, also known as rolled oats, have many different sizes, thicknesses and other characteristics depending on the size of oat groats passed between the rolls.
en.wikipedia.org Since a fortified city needed secure supplies, including supplies of flour and rolled groats, in the event of siege, numerous windmills were constructed on the bastions.
en.wikipedia.org Rations of meat and groats were also reduced, but the issue of sugar, confectionery and fats was increased instead.
en.wikipedia.org It may be ground fine, medium, or coarse, or rolled, or the groats may be chopped in two or three pieces to make what is described as pinhead oatmeal.
en.wikipedia.org