New Wave is a rock n' roll sub-genre that gained popularity in the late 1970s and early 1980's, due largely to its heavy presence in videos shown on MTV.
First perceived as a slightly safer, more watered-down version of punk rock, the earliest New Wave practitioners were a rag-tag bunch of roots rockers like Elvis Costello and Nick Lowe, and so-called "skinny tie" bands like the Cars and the Knack.
By the eighties however, New Wave came to be an all-purpose term characterizing anything that wasn't disco or metal. New Wave came to mean everything from the retro rock of the Romantics, Joan Jett, and the Go-Gos to the synth pop of Human League, Flock Of Seagulls, and Duran Duran.
At about the same time, a new breed of fashion conscious English metal bands like Def Leppard rose to prominence, that was tagged the New Wave of British Heavy Metal (or NWOBHM), which only further confused things. By the end of the eighties, with MTV's influence in decline and new genres like grunge emerging, New Wave's prominence had begun to fade.
Today, New Wave is largely viewed nostalgically by its fans, who nonetheless continue to blog about it at sites like Lost Bands Of The New Wave Era and the New Wave Diva.