short for drum 'n' bass. a style of electronica that incorporates fast tempos (150~180 bpm) syncopated breakbeats, and a heavy bassline. can incorporate various styles of other music; jazz, funk, hip-hop, are the most common. Sometimes called the 'black man's techno'. often times the word is used interchangibly with jungle, but a lot of people think that jungle and dnb are different. sub-genres include ambient dnb, techstep, 2-step, darkstep, etc. a man named roni size, who isn't that popular now, basically started the whole style of music. its cool.
if you want to hear some dnb, check out:
i went to a dnb rave by J. Majik and i had a blast.