In American and Canadian television, a midseason replacement is a television series that premieres in the second half of the traditional television season, usually between January and May. Midseason replacements usually take place after a show that was in the fall schedule was canceled or put on hiatus, or a program had a shortened season for some other reason which resulted in a time slot that needed filling.
This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)