The half-court line in basketball is a line on a basketball court that is located in the exact center, dividing the court equally into two pieces. It is also known as the timeline and the midcourt line. The half-court line separates the frontcourt from the backcourt and is used to determine a backcourt violation.
The frontcourt is the part of the court that the offense is attacking, while the ball is moved through the backcourt to get there. The half-court line is 50 feet long and is 47 feet from each baseline.
A backcourt violation occurs when the ball crosses the half-court line before returning to the backcourt while being possessed by the same team. This usually happens when a player in the frontcourt passes to a player not yet established in the frontcourt. A backcourt violation results in a loss of possession. You can learn more about backcourt violations in the Basketball Backcourt Violation tutorial