Block Programming
1. Block programming or television block is a strategy of broadcast programming and radio programmers. Block programming can simply be defined as arranging programs on radio or television so that similar programs or programs of the same sort of genre are aired one after another. The concept is to provide similar programming to keep the viewers interested in watching…Notable examples of block programming was NBC’s Thursday evening “Must See TV” lineup, which included two hours of sitcoms and one hour of ER, and Channel 4’s “T4” program which often ran sitcoms like Friends back-to-back for an hour or more. This strategy is particularly common in cable television, where reruns are assembled into similar blocks to fill several hours of generally little-watched daytime periods. A particularly long program block, especially one that does not air on a regular schedule, is known as a marathon.
Source: Wikipedia