The phrase "annual picnic" refers to a gathering or outdoor event that happens once a year, where people come together to eat food, play games, and have fun. Full definition
You're invited to attend Heartland's Third Annual Picnic for Freedom. (heartland.org)
Early pioneers, such as Hewlett - Packard Co., gave gifts to newlyweds and new parents, hosted annual picnics and showered employees with free snacks and coffee. (articles.latimes.com)
When he's asked to help plan his company's annual picnic alongside bubbly British import Fiona (Gemma Arterton), Jerry builds up the nerve to ask her on a date. (blog.bullz-eye.com)