Noun
speed metal (uncountable)
(music) A genre of heavy metal characterized by an extremely swift, rhythmic style.
A lot of power-pop comes out of LA, a lot of speed metal comes out of New York. Layne Staley
Speed metal eventually evolved into thrash metal. citation Although many tend to equate the two subgenres, others argue that there is a distinct difference between them. Source: Internet
For infobox Speed metal is an extreme subgenre of heavy metal music that originated in the late 1970s from new wave of British heavy metal (NWOBHM) roots. Source: Internet