picnic

a day devoted to an outdoor social gathering

any undertaking that is easy to do

any informal meal eaten outside or on an excursion

Formerly, an entertainment at which each person contributed some dish to a common table; now, an excursion or pleasure party in which the members partake of a collation or repast (usually in the open air, and from food carried by themselves).

eat alfresco, in the open air

To go on a picnic, or pleasure excursion; to eat in public fashion.