c. 1300, "first big meal of the day" (eaten between 9 a.m. and noon), from Old French disner "breakfast" (11c.), noun use of infinitive disner (Modern French dîner) "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).
Always used in English for the main meal of the day, but the time of that has gradually shifted later.
In medieval and modern Europe the common practice, down to the middle of the eighteenth century, was to take this meal about midday, or in more primitive times even as early as 9 or 10 A.M. In France, under the old régime, the dinner-hour was at 2 or 3 in the afternoon; but when the Constituent Assembly moved to Paris, since it sat until 4 or 5 o'clock, the hour for dining was postponed. The custom of dining at 6 o'clock or later has since become common, except in the country, where early dinner is still the general practice. [Century Dictionary, 1897]
The change from midday to evening began with the fashionable classes. Compare dinette.
Dinner-time is attested from late 14c.; dinner-hour is from 1750. Dinner-table is from 1784; dinner-jacket from 1852; dinner-party by 1780. Childish reduplication din-din is attested from 1905.
Despite the form lunching in the 1650s source OED discounts that it possibly could be from lunch (v.), which is first attested more than a century later. It suggests perhaps an analogy with truncheon, etc., or to simulate a French origin. Especially in reference to an early afternoon meal eaten by those who have a noontime dinner.
mid-13c., soper, "the last meal of the day," from Old French soper "evening meal," noun use of infinitive soper "to eat the evening meal," which is of Germanic origin (see sup (v.1)).
Formerly, the last of the three meals of the day (breakfast, dinner, and supper); now applied to the last substantial meal of the day when dinner is taken in the middle of the day, or to a late meal following an early evening dinner. Supper is usually a less formal meal than late dinner. [OED]
Applied since c. 1300 to the last meal of Christ.
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.
The Court dinner-hour, in the reign of George III., was at the Hanoverian hour of four o'clock. During the reign of George IV. it gradually crept up to six o'clock, and finally became steady at the Indian hour of seven, and so remained until the reign of Her Most gracious Majesty, when the formal Court dinner-hour became eight o'clock. These innovations on the national hours of meals did not meet the approval of the medical faculty, and in consequence a dinette at two o'clock was prescribed. This has ever since been the favourite Court meal, being in reality a substantial hot repast, which has exploded the old-fashioned luncheon of cold viands. [The Queen newspaper, London, quoted in Imperial Dictionary, 1883]