askchapo

Baseball specific one: "ground-rule double" colloquially used almost all the time to mean "automatic double." If a batted ball bounces on the warning track and goes over an outfield wall, it's an "automatic double," that's what it's called in the rulebook and that's a universal rule regardless of what ballpark the game is played at. "Ground rules" are specific to the ballpark, like a ball getting stuck in the ivy at Wrigley Field, or the catwalks on the dome in Tampa. One of those catwalks is a ground-rule home run, but nobody ever says that. For some reason, "ground-rule double" is ubiquitous for automatic double, but actual ground-rule stuff is very rare.