1 a : a meal that is eaten outdoors especially during a trip away from home
We decided to have a picnic on the beach.
We ate our picnic by the lake.
1 b : a trip or party that includes a meal eaten outdoors
This weekend I have a family picnic [=a picnic with family members] to go to.
The annual school/company picnic is this weekend.
◊ If you go on a picnic, you go somewhere to have a picnic.
Let's go on a picnic today.
2 informal : something that is pleasant or easy
This winter is a picnic compared with last year's.
— often used in negative statements
Breaking a leg is no picnic. [=breaking a leg is not a pleasant experience]
Being president isn't exactly a picnic. [=being president is not easy]