The meal in three course meal and the meal in oatmeal have no linguistic connection to each other. Like the word meat, the meal that refers to breakfast, lunch, and dinner derives ultimately from an Indo-European source meaning measure. Because people have long eaten at appointed or “measured” times—such as noon—this ancient word for measure developed into the Old English word mad, meaning appointed eating time. First recorded in the ninth century, the Old English mael became our modern meal and even today its original sense of appointed time persists so strongly that most people hesitate to call food eaten at an unconventional hour—such as three in the afternoon—a meal. Closely related to the culinary meal is the meal in piecemeal, literally meaning to measure out piece by piece. In contrast, the meal in oatmeal and cammed derives from a completely different source, namely, an Indo-European word meaning to grind, since foods such as oatmeal are produced by grinding grain. Also from this Indo-European source developed words such as mill, the place where grain is ground, and, via Latin, molar, the name of the teeth that grind food to smithereens. Because grain meal is soft and utterly inoffensive, meal may in turn have given rise to the word mellow (which, surprisingly, has no connection to the equally soft and inoffensive marshmallow).
Food eaten at a particular time.
Portion of food eaten at a particular time to satisfy the appetite.