Grunge is a term used particularly by the media in hopes of classifying the unusual, unique and different sounds that emerged from the Seattle scene during the late 1980's and good portion of the 1990's. However, some Music Historians argue that grunge had existed long before these decades, suggesting that musicians such as Neil Young and The Wipers were the first artists to use the "grunge effect" in their musical compositions. This term indicated the murky, "dirty" sounds that originated from guitars from various artists such as: Soundgarden, Nirvana, Pearl Jam, The Melvins, Bush, Green River, Alice In Chains, Candlebox, Helmet, Love Battery, Mad Season, Porno for Pyros, Screaming Trees, Silver Chair, The Stone Roses, Stone Temple Pilots, Temple of The Dog and many other bands. Yet, hard and heavy metal rock had been embedded in grunge's roots, since most of the inspirations originated from "raw rock" during the 1960's - 1970's.
Another analogy associated with grunge music is a term known as "The Explosion of The Big Four". This described the sudden explosion of underground thrash/analytical-punk/metal music in the mainstream. The "Big Four" refers to the main bands that had caused grunge music to be such a success: Alice In Chains, Nirvana, Pearl Jam and Soundgarden.
Furthermore, the era in which grunge became popular had other causes as well. Most of the younger generations rebelled against parents and society, causing them to turn to music in which they could relate to, instead of the typical 1980's hair metal scene, which included artists such as Poison and Motley Crue, who typically wrote about unrealistic and uncreative occurrences that did not deeply impact society.