Olympic Weightlifting is a sport that involves lifting a loaded barbell overhead by two different methods. The first of those methods is the Snatch, shown below. The Snatch is when the barbell is moved from the ground to overhead in one single movement.
The second of those methods is the Clean and Jerk. In this movement, the barbell is moved from the ground to the shoulder (the Clean) and from the shoulder to overhead in a separate movement (the Jerk). This method is shown below.
In competition, an athlete has 3 attempts to get as large a number on each of the contested lifts as possible, then those numbers are added together to find a Total, which determines their placement in the competition. This total is also the determining factor for athletes trying to qualify for higher level competitions, such as the American Open Series, American Open Finals, Nationals, and international events (though this is more complicated than just posting a qualifying total) such as the Roma Cup, Pan American Championships, and the World Championships.