Answer: Baseball

“Alright folks, let’s go over the ground rules…” is how just about every group activity starts out, be it a white water rafting trip or an afternoon playing laser tag. The “ground rules” are the basic rules for behavior, safety, and so on, for the given activity.

While the term now means the basic rules, and has been used in that fashion since the 1950s, it was originally a literal term. The ground rules were the explicit rules for specific playing fields, or grounds, as they were called and the first known example of such use dates back to 1890.

Despite the jump in the mid-20th century to general usage, the term is still in use with baseball fields, and per Major League Baseball regulations, individual stadiums have their own ground rules which are designed to take into account the design of the stadium. For example, one of the ground rules at Wrigley Field, where the Chicago Cubs play, concerns the thick ivy on the outfield fence—if a ball becomes lodged in the ivy, two bases are awarded to the batter and all runners. If the ball falls out of the ivy after striking the fence, it remains in play.