Word History: In Middle English dinner meant "breakfast," as did the Old French word disner, or diner, which was the source of our word. The Old French word came from the Vulgar Latin word *disiūnāre, meaning "to break one's fast; that is, to eat one's first meal," a notion also contained in our word breakfast. The Vulgar Latin word was derived from an earlier word, *disiēiūnāre, the Latin elements of which are dis-, denoting reversal, and iēiūnium, "fast." Middle English diner not only meant "breakfast" but, echoing usage of the Old French word diner, more commonly meant "the first big meal of the day, usually eaten between 9 AM and noon." Customs change, however, and over the years we have let the chief meal become the last meal of the day, by which time we have broken our fast more than once.