PICNIC

• pic‧nic [countable]
• 1 if you have a picnic, you take food and eat it outdoors, especially in the country:
• We decided to have a picnic down by the lake.
• go on/for a picnic
• We could go on a picnic today.
• a picnic table
• There is free parking for visitors, as well as a restaurant and picnic area (=a special area with tables where people can have a picnic).
• picnic site/spot/place (=a place that is suitable or pleasant for a picnic)
• We found a lovely picnic spot by the river.
• picnic basket/hamper (=a container in which you can carry food for a picnic)
• ! Do not say 'do a picnic' or 'make a picnic'. Say have a picnic.
• 2 British English the food that you take to eat outdoors on a picnic:
• We'll take a picnic with us.
• picnic lunch/tea/supper
• We ate our picnic lunch by the river.
• 3

  be no picnic

  informal if something is no picnic, it is very difficult and needs a lot of effort or hard work:
• Bringing up six children is no picnic!
• WORD FOCUS: meal 
• meals at different times of day: breakfast, brunch, lunch, tea British English, dinner, supper
• a meal outside: picnic, barbecue also barbie informal, cookoutAmerican English
• when you quickly eat a little food : snack, a bite to eat
• a very big meal for a lot of people: banquet, feast
• parts of a meal: starter British English, appetizer American English(the first course)
• main course/entree especially AmE, side dish (eaten with the main course)
• dessert also pudding sweet British English (sweet food eaten at the end of the meal)
• 
  
• ➔ See also meal

Definition from the Longman Dictionary of Contemporary English
Advanced Learner's Dictionary.