Princeton's WordNet

1. triple crown(noun)

   (horse racing) a title won by a horse that can win the Kentucky Derby and the Belmont Stakes and the Preakness

2. triple crown(adj)

   (baseball) an unofficial title won by a batter who leads the league in hitting average, runs batted in, and home runs

3. triple-crown(adj)

   of a horse that has won the Kentucky Derby and the Belmont Stakes and the Preakness races

4. triple-crown(adj)

   unofficial championship title for player who heads the league in batting average and home runs and runs batted in