c. 1300, dinen, "eat the chief meal of the day, take dinner;" also in a general sense "to eat," from Old French disner "to dine, eat, have a meal" (Modern French dîner), 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, do the opposite of" (see dis-) + Late Latin jejunare "to fast," from Latin iejunus "fasting, hungry, not partaking of food" (see jejune).
Transitive sense of "give a dinner to" is from late 14c. To dine out "take dinner away from home" is by 1758.