Heavy metal (or simply metal) is a genre of rock music that developed in the late 1960s and early 1970s, largely in the United Kingdom and to a lesser extent in the United States. With roots in blues rock, psychedelic rock, and acid rock, heavy metal bands developed a thick, massive sound, characterized by distortion, extended guitar solos, emphatic beats, and loudness. The lyrics and performances are sometimes associated with aggression and machismo.
Power metal is a subgenre of heavy metal combining characteristics of traditional heavy metal with speed metal, often within symphonic context. Generally, power metal is characterized by a faster, lighter, and more uplifting sound, in contrast with the heaviness and dissonance prevalent, for example, in extreme metal. Power metal bands usually have anthem-like songs with fantasy-based subject matter and strong choruses, thus creating a theatrical, dramatic and emotionally "powerful" sound..
Progressive metal (sometimes known shortened as prog metal) is a broad fusion music genre melding heavy metal and progressive rock, combining the loud "aggression" and amplified guitar-driven sound of the former with the more experimental, cerebral or "pseudo-classical" compositions of the latter. One of these experimental examples introduced to modern metal was djent. The music typically showcases the extreme technical proficiency of the performers and usually uses unorthodox harmonies as well as complex rhythms with frequent meter changes and intense syncopation.
Melodic death metal (also referred to as melodeath) is a subgenre of death metal that employs highly melodic guitar riffs, often borrowing from traditional heavy metal. The style originated and developed in Sweden (pioneered by At the Gates, Dark Tranquillity and In Flames) and the United Kingdom (pioneered by Carcass) around 1993. The Swedish death metal scene did much to popularise the style, soon centering in the "Gothenburg metal" scene.
Extreme metal is a loosely defined umbrella term for a number of related heavy metal music subgenres that have developed since the early 1980s. It has been defined as a "cluster of metal subgenres characterized by sonic, verbal, and visual transgression".
The term usually refers to a more abrasive, harsher, underground, non-commercialized style associated with the speed metal, thrash metal, black metal, death metal, and doom metal genres. Hardcore punk has been considered an integral part of the development of extreme metal, in the case of song structure and speed, in every case other than doom metal.