The term for hitting the ball before it bounces on your side of the court is a volley. A volley is usually struck near the net, but players can also hit one from the service line, mid-court, or even close to the baseline.
Unlike a groundstroke, which is played after the ball has bounced, a volley takes the ball out of the air and gives the opponent less time to react. Players generally use a compact punching motion rather than a long backswing, because the ball may arrive quickly and there is little time to prepare.
Volleys are central to serve-and-volley tactics, in which a player serves and immediately moves forward to attack at the net. They are also common in doubles, where net players must react rapidly to passing shots and angled returns.
Several nearby terms can cause confusion. A half-volley is played immediately after the ball bounces, while a lob sends the ball high over an opponent. A drop volley is still a volley, but it is hit softly so that it lands short and close to the net.