Definition from Wiktionary, the free dictionary
luncheon (plural luncheons)
- A formal meal served in the middle of the day.
1963, Margery Allingham, chapter 2, The China Governess:
- Now that she had rested and had fed from the luncheon tray Mrs. Broome had just removed, she had reverted to her normal gaiety. She looked cool in a grey tailored cotton dress with a terracotta scarf and shoes and her hair a black silk helmet.
- (obsolete) A lump of food.
- (obsolete) A portion of food taken at any time except at a regular meal; an informal or light repast.