(Baseball) a hit that allows the player to go around all four bases, generally by hitting the ball out of play. Also called a home run. This term comes from the fact that such hits are often long balls, as they tend to travel far. The word "long" here is used in its early modern sense of "lengthy," but it also means "to the center field fence (which is usually considered to be about 450 feet from home plate)." A long ball is thus one that goes beyond what a normal hit would do. In actuality, only about 10% of all hits are long balls, but because most extra-base hits are singles, it seems like more than 10%. Long balls are valuable, because they score lots of runs and allow players to reach base easily. Thus, it is desirable for hitters to hit them well. A long ball that reaches the outfield is usually caught by one of the defenders, although some are hit into certain types of outs (i.'thout any runners on base). If a long ball gets past the first defender, an error is made on the part of the defense; otherwise, it is called perfect.