<P> Birmingham's Black Sabbath had developed a particularly heavy sound in part due to an industrial accident guitarist Tony Iommi suffered before cofounding the band . Unable to play normally, Iommi had to tune his guitar down for easier fretting and rely on power chords with their relatively simple fingering . The bleak, industrial, working class environment of Birmingham, a manufacturing city full of noisy factories and metalworking, has itself been credited with influencing Black Sabbath's heavy, chugging, metallic sound and the sound of heavy metal in general . Deep Purple had fluctuated between styles in its early years, but by 1969 vocalist Ian Gillan and guitarist Ritchie Blackmore had led the band toward the developing heavy metal style . In 1970, Black Sabbath and Deep Purple scored major UK chart hits with "Paranoid" and "Black Night", respectively . That same year, two other British bands released debut albums in a heavy metal mode: Uriah Heep with Very' Eavy...Very' Umble and UFO with UFO 1 . Bloodrock released their self - titled debut album, containing a collection of heavy guitar riffs, gruff style vocals and sadistic and macabre lyrics . The influential Budgie brought the new metal sound into a power trio context, creating some of the heaviest music of the time . The occult lyrics and imagery employed by Black Sabbath and Uriah Heep would prove particularly influential; Led Zeppelin also began foregrounding such elements with its fourth album, released in 1971 . In 1973, Deep Purple released the song Smoke on the Water, with the iconic riff that's usually considered as the most recognizable one in "heavy rock" history, as a single of the classic live album Made in Japan . </P> <P> On the other side of the Atlantic, the trend - setting group was Grand Funk Railroad, described as "the most commercially successful American heavy - metal band from 1970 until they disbanded in 1976, (they) established the Seventies success formula: continuous touring". Other influential bands identified with metal emerged in the U.S., such as Sir Lord Baltimore (Kingdom Come, 1970), Blue Öyster Cult (Blue Öyster Cult, 1972), Aerosmith (Aerosmith, 1973) and Kiss (Kiss, 1974). Sir Lord Baltimore's 1970 debut album and both Humble Pie's debut and self - titled third album were all among the first albums to be described in print as "heavy metal", with As Safe As Yesterday Is being referred to by the term "heavy metal" in a 1970 review in Rolling Stone magazine . Various smaller bands from the U.S., U.K, and Continental Europe, including Bang, Josefus, Leaf Hound, Primeval, Hard Stuff, Truth and Janey, Dust, JPT Scare Band, Frijid Pink, Cactus, May Blitz, Captain Beyond, Toad, Granicus, Iron Claw, and Yesterday's Children, though lesser known outside of their respective scenes, proved to be greatly influential on the emerging metal movement . In Germany, Scorpions debuted with Lonesome Crow in 1972 . Blackmore, who had emerged as a virtuoso soloist with Deep Purple's highly influential album Machine Head (1972), left the band in 1975 to form Rainbow with Ronnie James Dio, singer and bassist for blues rock band Elf and future vocalist for Black Sabbath and heavy metal band Dio . Rainbow with Ronnie James Dio would expand on the mystical and fantasy - based lyrics and themes sometimes found in heavy metal, pioneering both power metal and neoclassical metal . These bands also built audiences via constant touring and increasingly elaborate stage shows . </P> <P> As described above, there are arguments about whether these and other early bands truly qualify as "heavy metal" or simply as "hard rock". Those closer to the music's blues roots or placing greater emphasis on melody are now commonly ascribed the latter label . AC / DC, which debuted with High Voltage in 1975, is a prime example . The 1983 Rolling Stone encyclopedia entry begins, "Australian heavy - metal band AC / DC". Rock historian Clinton Walker writes, "Calling AC / DC a heavy metal band in the seventies was as inaccurate as it is today...(They) were a rock' n' roll band that just happened to be heavy enough for metal". The issue is not only one of shifting definitions, but also a persistent distinction between musical style and audience identification: Ian Christe describes how the band "became the stepping - stone that led huge numbers of hard rock fans into heavy metal perdition". </P> <P> In certain cases, there is little debate . After Black Sabbath, the next major example is Britain's Judas Priest, which debuted with Rocka Rolla in 1974 . In Christe's description, </P>

Where does the name heavy metal come from