Heavy Metal -A military term for heavily fortified tanks/guns etc. The expression first appears in print in the 1964 'Nova Express' novel by William Burroughs. It isn't clear who first appropriated the term to refer to loud rock music. The US rock music critic Lester Bangs, while working for Creem magazine, used the expression in 1968 to describe a performance of the band MC5 (Motor City Five) from Detroit and many regard this as the origin of the current usage of the phrase. Soon other bands, many of which used 'heavy metal' imagery in their names and song lyrics, e.g. Led Zeppelin, Iron Butterfly, were labelled as such.