Turnovers is another of the basketball statistics that you don't want to have a high number in. These are very bad for you and your team, as a turnover is when you do something besides miss a shot that gives the other team possession of the ball (so you "turn it over" to the defense).
Things like having the ball stolen from you, having a violation (traveling, double dribble, etc.), and throwing the basketball out of bounds are considered turnovers.