A block, or blocked shot, is a defensive play in which a defender deflects a field goal attempt before it reaches the basket, without committing a foul.
The block is defence at its most visible: a shot, launched and on its way, knocked aside by a defender's hand. To count, the deflection must happen while the ball is rising or at its peak; touch it on the way down toward the rim and the same play becomes goaltending and points for the offence. The blocked shot is credited in the box score to the defender, and the shooter is charged with an attempt and a miss.
Blocks were not officially counted until the 1973 to 1974 season, which splits the record book in two: Hakeem Olajuwon leads the official career list with 3,830, while Russell and Chamberlain's true totals are lost to the era before counting. Chase down blocks, the guard's sprinting rejection from behind, became the modern era's signature defensive highlight, none more famous than LeBron James's block in Game Seven of the 2016 Finals.
As analysis, blocks measure both protection and risk, since a defender chasing blocks can leave the glass exposed. For quizzes, the term carries record questions, era questions, and rules questions at once, all hanging on the ascent versus descent distinction.
In use"The block at the rim with ten seconds left preserved the one point lead."