Grunge (sometimes referred to as the Seattle sound) is a subgenre of alternative rock that emerged during the mid-1980s in the American state of Washington, particularly in the Seattle area. Inspired by hardcore punk, heavy metal, and indie rock, grunge is generally characterized by heavily distorted electric guitars, contrasting song dynamics, and apathetic or angst-filled lyrics. The grunge aesthetic is stripped-down compared to other forms of rock music, and many grunge musicians were noted for their unkempt appearances and rejection of theatrics.

The early grunge movement coalesced around Seattle independent record label Sub Pop in the late 1980s. Grunge became commercially successful in the first half of the 1990s, due mainly to the release of Nirvana's Nevermind and Pearl Jam's Ten. The success of these bands boosted the popularity of alternative rock and made grunge the most popular form of hard rock music at the time. However, many grunge bands were uncomfortable with this popularity. Although most grunge bands had disbanded or faded from view by the late 1990s, their influence continues to affect modern rock music.

Grunge is generally characterized by a sludgy guitar sound that uses a high level of distortion, fuzz and feedback effects. Grunge fuses elements of hardcore punk and heavy metal, although some bands performed with more emphasis on one or the other. The music shares with punk a raw sound and similar lyrical concerns. However, it also involves much slower tempos, dissonant harmonies, and more complex instrumentation вАУ which is reminiscent of heavy metal. Some individuals associated with the development of grunge, including Sub Pop producer Jack Endino and the Melvins, explained grunge's incorporation of heavy rock influences such as Kiss as "musical provocation". Grunge artists considered these bands "cheesy" but nonetheless enjoyed them; Buzz Osborne of the Melvins described it as an attempt to see what ridiculous things bands could do and get away with. In the early 1990s, Nirvana's signature "stop-start" song format became a genre convention.

Grunge concerts were known for being straightforward, high-energy performances. Grunge bands rejected the complex and high budget presentations of many musical genres, including the use of complex light arrays, pyrotechnics, and other visual effects unrelated to playing the music. Stage acting was generally avoided. Instead the bands presented themselves as no different from minor local bands. Jack Endino said in the 1996 documentary Hype! that Seattle bands were inconsistent live performers, since their primary objective was not to be entertainers, but simply to "rock out". Clothing commonly worn by grunge musicians in Washington consisted of thrift store items and the typical outdoor clothing (most notably flannel shirts) of the region, as well as a generally unkempt appearance. The style did not evolve out of a conscious attempt to create an appealing fashion; music journalist Charles R. Cross said, "[Nirvana frontman] Kurt Cobain was just too lazy to shampoo," and Sub Pop's Jonathan Poneman said, "This [clothing] is cheap, it's durable, and it's kind of timeless. It also runs against the grain of the whole flashy aesthetic that existed in the 80s."