Definition of: snowball

(snō′bôl′) noun
1. A small round mass of snow compressed to be thrown, as in sport.
2. The guelder–rose (Viburnum opulus): so called from its ball–shaped clusters of white flowers: also snowball bush or tree.
—v.i.
1. To throw snowballs.
2. To gain in size, importance, etc., as a snowball that rolls over snow.
—v.t.
3. To throw snowballs at.