What is the meaning of the word "triple crown"?

Definitions:

  1. in baseball, an unofficial title won by a batter who leads the league in hitting average, runs batted in, and home runs copy to clipboard noun
    • Winning the triple crown was part of what made the player an easy choice for their team. copy to clipboard
  2. in horse racing, a title won by a horse that can win the Kentucky Derby and the Belmont Stakes and the Preakness copy to clipboard noun
    • It is very rare for a jockey to ride a triple crown winner. copy to clipboard