luncheon
1580, nonechenche "light mid-day meal," from none "noon" + schench "drink," from O.E. scenc, from scencan "pour out." Altered by northern Eng. dial. lunch "hunk of bread or cheese" (1590), which probably is from Sp. lonja "a slice," lit. "loin." When it first appeared, luncheon meant "thick piece, hunk;" sense of "light repast between mealtimes" is from 1652, esp. in ref. to an early afternoon meal eaten by those who have a noontime dinner. Type of restaurant called a luncheonette is attested from 1924, Amer.Eng. Slang phrase out to lunch "insane, stupid, clueless" first recorded 1955, on notion of being "not there."

Sliced luncheon sausage is a common ingredient in kids lunches
down these parts.