Lunch is a meal that is taken in the early afternoon. The term was derived from "luncheon", which the OED reports from 1580, as a word for a meal that was inserted between more substantial meals, as during the eighteenth century what was originally called "dinner"— a word still sometimes used to mean a noontime meal in the British Isles, and in parts of the United States, Canada and Australia — was moved by stages later in the day and came in the course of the nineteenth century to be eaten at night, replacing the light meal called supper, which was delayed by the upper class to midnight.

In the United States,Thanksgiving dinner (and Christmas dinner) are still eaten at the old hours, usually between two and four in the afternoon.

In addition to its primary purpose, lunch can function as a form of entertainment, especially on weekends; a particularly fancy or formal lunch can be called a luncheon. Such lunches can be served at a restaurant, as a buffet or potluck, or as a sit-down feast. These events are very similar to festive suppers. Lunch, both simple and fancy, often includes dessert.