A round mass of snow pressed or roller together, or anything resembling such a mass.
- A mass of soft, wet snow packed into a ball that can be thrown, as in play.
- Chiefly Southern U.S. A cup of crushed or shaved ice flavored with colored syrup.
- Any of several plants having rounded clusters of white flowers, as the guelder rose and certain species of the arrowwood.
- To grow rapidly in significance, importance, or size: problems that snowballed by the hour.
- To throw snowballs.
- To cause to grow or increase rapidly.
- To throw snowballs at.