1. swelled out or filled with air or wind
2. moved in large waves or surges

Examples

• The curtains billowed in the breeze from the open window.
• Smoke billowed from the chimney on the cold morning.
• Her dress billowed around her as she walked.
• The sails billowed as the wind caught them.
• Steam billowed from the hot springs.
• The flag billowed proudly in the strong wind.
• Clouds of dust billowed behind the speeding car.