late 13c., from Old French disner (Modern French dîner) "to dine, eat, have a meal," originally "take the first meal of the day," from stem of Gallo-Roman *desjunare "to break one's fast," from Vulgar Latin *disjejunare, from dis- "undo" (see dis-) + Late Latin jejunare "to fast," from Latin iejunus "fasting, hungry" (see jejune).