Oat/əʊt/ Definition 1 of 2Pro Tip 1/3Food and Animals Oat refers to grains used in human food like oatmeal and as livestock feed. The farmer bought oat to feed his horses. Pro Tip 2/3Health Associations Oats are often associated with health, particularly in the context of breakfast foods. Adding oats to your diet can be beneficial for your heart. Pro Tip 3/3Culinary Uses In the kitchen, 'oat' can refer to various forms like flour or bran, used in recipes. She used oat flour to make gluten-free cookies.