Underground as an adjective commonly refers to something that is either below the ground or outside of public consciousness. As a proper noun, the Underground may refer to a subculture or the Metro (mass transit system).

The underground can also refer to:

• Karst topography, a landscape of distinctive dissolution patterns often marked by underground drainages
• Underground comix, a term for non-mainstream comics
• Organized crime, crime carried out systematically by formal criminal organizations
• Underground culture, a term to describe various alternative cultures
• Underground music, music that has a certain following despite a moderate commercial success
• Underground economy, commerce that is not taxed
• Underground film, cinema outside the commercial mainstream
• UK Underground, a 1960s countercultural movement in the United Kingdom
• Underground resistance, nickname used for some resistance movements
• Underground living, living below the ground's surface
• Underground hip hop, a style of hip hop music distinguished by beats, samples, and lyrics that differ from the general template of popular commercial hip hop
• London Underground, a metro system that covers the Greater London area
• Underground press, the alternative print media in the late 1960s and early 1970s
• Underground (Thelonious Monk album), a 1967 jazz recording by Thelonious Monk
• Underground (Keaggy album), a 1983 album by guitarist Phil Keaggy
• Underground (album), a 2001 album by Analog Pussy
• Underground (Electric Prunes album), a 1967 album by The Electric Prunes
• Underground (song), a 1986 single by David Bowie featured in the film Labyrinth
• Underground (stories), a collection of biographical short stories of victims of the Aum Shinrikyo sarin attack on the Tokyo subway by Murakami Haruki
• Underground (film), a film concerning Yugoslavia, directed by Emir Kusturica
• Underground and its sequel, Underground 2, racing video games, developed and published by Electronic Arts
• Underground (role playing game), a satirical role playing game released by Mayfair Games in 1993
• The Underground (concert venue), a Christian concert venue in the Cincinnati area
• Sounds of the Underground, a North American music tour of mainly underground metal bands
• Underground (Stargate Atlantis), a Stargate Atlantis television series episode

Underground

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