Match-up zone defense is a type of defense used in the game of basketball. It is commonly referred to as a "combination" defense, as it combines certain aspects of man-to-man defense and zone defense. Perhaps the most famous user of the match-up zone was John Chaney, former head basketball coach at Temple University.
With the match-up zone defense, the on-ball defender will play tight as if he was playing man-to-man. At the same time, the zone away from the ball will resemble "help-side" man-to-man defense. This creates one of the advantages for the match-up zone, as it may confuse the opponent as to what defense you are actually playing. The match-up zone also resembles a "switching man-to-man" defense, where the big men stay down low in the post and the guards stay around the perimeter.