On this Wikipedia the language links are at the top of the page across from the article title. A picnic party assembling in Columbus, Ohio, c. History shows us that the idea of a meal that was jointly contributed to and enjoyed out-of-doors was essential to picnic side dishes 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. Some picnics are a potluck, where each person contributes a dish for all to share.