A Procedural is a cross-genre type of literature, film, or television program involving a sequence of technical detail. A documentary film may be written in a procedural style to heighten narrative interest.
In television, "procedural" specifically refers to a genre of programs in which a problem is introduced, investigated and solved all within the same episode. These shows tend to be hour-long dramas, and are often (though not always) police or crime related.
The general formula for a police procedural involves the commission or discovery of a crime at the beginning of the episode, the ensuing investigation, and the arrest or conviction of a perpetrator at the end of the episode.
Modern examples of this genre are the Law & Order, CSI & NCIS franchises. House is an example of a non-crime-related procedural.