Swing: "some notes with equal written time values are performed with unequal durations, usually as alternating long and short" (wikipedia with a decent explanation wow). accents and short rests (pauses) are also used to create a "swing feel"

swing is kind of difficult to explain fully in a traditional musical fashion; you really have to hear it, and feel it if you're playing an instrument. Listen to some jazz, big band, bebop, or like someone said above, house is usually swung.