'Snowball bush' definitions:

Definition of 'Snowball bush'

From: GCIDE

Snowball \Snow"ball`\, n.
1. A round mass of snow pressed or roller together, or anything resembling such a mass. [1913 Webster]
2. (Bot.) The Guelder-rose. [1913 Webster]
3. (Bot.) a shrub of the genus Viburnum, having large clusters of white flowers. [PJC]
Snowball bush or Snowball tree (Bot.), the Guelder-rose.
a snowball's chance in hell, [Colloq.] no chance; an infinitesimal chance. [1913 Webster +PJC]