Everything About Fiction You Never Wanted to Know.

"I know this is a sitcom, but no one can be this stupid."
Brendon, in Home Movies (an animated sitcom)

The term Sitcom is a contraction of "Situation Comedy". Originally, sitcoms were broadcast on the radio. Before long, they progressed to television; the Ur-Sitcom on TV is I Love Lucy, which pioneered many of the technical and comedic techniques used to this day, including Three Cameras, but the first television sitcom is generally agreed to have been 1946's Pinwright's Progress on the BBC (all footage is lost, however).

See also Comedy Tropes.