LUNCHEON, in present usage the name given to a meal between breakfast and tea or dinner. When dinner was taken at an early hour, or when it is still the principal midday meal, luncheon was and is still a light repast. The derivation of the word has been obscured, chiefly owing to the attempted connexion with " nuncheon," with which the word has nothing to do etymologically. " Luncheon " is an extended form of " lunch " (another form of " lump," as " hunch " is of " hump "). Lunch and luncheon in the earliest meanings found are applied to a thick piece of bread, bacon, meat, etc.
The word "nuncheon," or "nunchion," with which "luncheon" has been frequently connected, appears as early as the 1410 century in the form noneschenche. This meant a refreshment or distribution, properly of drink, but also accompanied with some small quantity of meat, taken in the early afternoon. The word means literally " noon-drink," from none or noon, i.e. nona hora, the ninth hour, originally 3 o'clock P.M., but later " midday " the church office of "nones," and also the second meal of the day, having been shifted back and schenchen, to pour out; cf. German schenken, which means to retail drink and to give, present. Schenche is the same as "shank," the shin-bone, and the sense development appears to be shin-bone, pipe, hence tap for drawing liquor. See also Skeat, Etymological Did. of English Language (1910), s.v. " nunchion."
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)