1. softball(n = noun.artifact) playground ball - ball used in playing softball;
is a kind of ball
2. softball(n = noun.act) softball game - a game closely resembling baseball that is played on a smaller diamond and with a ball that is larger and softer;
is a kind of baseball, baseball game
Antonym: hardball
softball, n.
1 a ball like a baseball but softer and larger.
2 a modified form of baseball using this.