From The TV IV
Procedural (often called police procedural) is a term used to describe a television drama that details the process of solving a mystery, particularly a crime. Typically, little attention is paid to long term plot arcs and character development (as opposed to serialized shows), and each episode stands on its own.
The prototypical TV procedural is Dragnet. Since the 1990s, the success of such shows as Law & Order and CSI has resulted in a number of spinoff and copycat shows, and throughout the 2000s, this has been one of the more popular formats on television.