In baseball, batting does not only mean a batter's bat makes contact with the baseball. In order to successfully get a hit, the baseball must land in fair territory and the batter-runner must safely reach base. There are many different ways a batter attempts to hit the baseball:
A clean hit is a baseball that lands in fair territory without having been touched by a fielder. It commonly refers to a baseball that travels through the infield without being touched by an infielder, or a baseball that goes over an outfielder's head.
A line drive is a hard-hit baseball that travels fast through the air, but relatively low/close to the ground without bouncing. Line drives can be hard to field unless hit in a fielder's direction, and have a fairly high tendency to become successful hits.