In baseball, a triple is the act of a batter safely reaching third base after hitting the ball, with neither the benefit of a fielder's misplay (see error) nor another runner being put out on a fielder's choice.
[2][3] Triples have become somewhat rare in Major League Baseball, less common than both the double and the home run.
It also requires the batter's team to have a good strategic reason for wanting the batter on third base, as a stand-up double is sufficient to put the batter in scoring position and there will often be little strategic advantage to risk being tagged out whilst trying to stretch a double into a triple (although reaching third base with fewer than two outs could potentially allow the runner to reach home plate on a sacrifice fly).
On the extreme, the triple may be stretched into the very rare inside-the-park home run.
The trend for modern ballparks is to have smaller outfields (generally increasing the number of home runs), ensuring that the career and season triples leaders mostly consist of those who played early in Major League Baseball history, particularly in the dead-ball era.