1a. the short "teaser" that attempts to entice you to continue to watch the show, or b. recaps what went on during that portion of the show
2. Needless filler for shows lacking content (see also: postmercial)
The premercial shows two contestants getting into a catfight! I can't wait for the next segment!
Why does Iron Chef America always have a 5-minute premercial recapping what just happened? Do they think we already forgot what happened 10 minutes ago?