A picnic is a meal taken outdoors (al fresco) as part of an excursion, especially in scenic surroundings, such as a park, lakeside, or other place affording an interesting view, or else in conjunction with a public event such as preceding an open-air theater performance, and usually in summer. It is different from other meals because it requires free time to leave home.

History shows us that the idea of a meal that was jointly contributed to and enjoyed out-of-doors was essential to picnic from the early 19th century.

Picnickers like to sit on the ground on a rug or blanket. Picnics can be informal with throwaway plates or formal with silver cutlery and crystal wine glasses. Tables and chairs may be used but this is less common.

Outdoor games or some other form of entertainment are common at large picnics. In public parks, a picnic area generally includes picnic tables and possibly built-in grills, water faucets (taps), garbage (rubbish) containers and restrooms (toilets).

Some picnics are a potluck, where each person contributes a dish for all to share. The food eaten is rarely hot, instead taking the form of deli sandwiches, finger food, fresh fruit, salad and cold meats. It can be accompanied by chilled wine, champagne or soft drinks.