barbie
Word family
Synonym discussion
Sense: noun/2
For this sense, barbie is an informal Australian short form of barbecue. Barbecue is the fuller and more widely understood word, so it is safer outside Australian contexts. Cookout is close in meaning, but it is mainly American English. Picnic also describes eating outside, yet it does not strongly suggest that food is grilled on the spot. If Australian friends say they are having a barbie, they usually mean a relaxed social meal with grilled food. If you are writing for an international audience, barbecue is the clearer choice. You might go to a family barbie by the beach, but take sandwiches to a picnic in the park.
Etymology
Barbie is a casual shortened form of barbecue. The shorter form became common in Australian English, especially in everyday speech about outdoor cooking and social meals.