1. a small bag made of thin rubber or plastic that is filled with air or gas and used as a toy or decoration
2. a large bag filled with hot air or gas that can carry people through the sky

1. to suddenly become much larger in size, amount, or importance
2. to travel in a hot air balloon

Examples

• The children played with colorful balloons at the birthday party.
• She tied a red balloon to her wrist so it wouldn’t float away.
• We took a hot air balloon ride over the valley.
• The balloon drifted slowly across the morning sky.
• Healthcare costs have ballooned over the past decade.
• The project’s budget ballooned from $1 million to $5 million.
• They decided to balloon over the countryside for their anniversary.