1. the sport or activity of riding in a hot air balloon

1. present participle of balloon: to swell or expand rapidly
2. present participle of balloon: to increase quickly in amount or size

1. expanding or increasing rapidly

Examples

• Hot air ballooning is a popular tourist activity in Napa Valley.
• The company offers ballooning tours over the countryside.
• Healthcare costs are ballooning out of control.
• The balloon was ballooning as hot air filled it.
• The national debt is ballooning at an alarming rate.
• Her dress had ballooning sleeves that caught the wind.
• The ballooning population put strain on city resources.