Explain the term 'jam' in roller derby.

The term 'jam' in roller derby specifically refers to a timed period during a bout when jammers, the offensive players, attempt to score points by making laps around the track while navigating through opposing blockers. Each jam usually lasts two minutes, but can end early if the lead jammer calls it off by placing their hands on their hips. Scoring points occurs when a jammer successfully laps opposing skaters, earning a point for each blocker they pass. This scoring mechanism is fundamental to the game, making the 'jam' a crucial and dynamic component of roller derby play. The excitement of each jam builds with the strategic interplay between trying to score and defending against the opponent's jammers, creating a fast-paced and engaging environment.