Drain
Drain may refer to:

Objects and processes
Drain (plumbing), a fixture that provides an exit-point for waste water or for water that is to be re-circulated on the side of a road
Floor drain
Drain (surgery), a tube used to remove pus or other fluids from a wound
Drainage, the natural or artificial removal of surface and sub-surface water from a given area
French drain, a system that redirects surface water and groundwater away from an area
Slot drain
Storm drain, a system of collecting and disposing of rain water in an urban area
Drain (transistor), a terminal in a field effect transistor

Art and entertainment
Drain (band), an American noise rock band
Drain (comics), a comic book series starring a vampire
Drain STH, a disbanded female hard-rock band from Sweden
"Drain", by X Japan from Dahlia

Places
Drain, Oregon, a city in Douglas County, Oregon, United States
Drain, Maine-et-Loire, a commune in France
Waterloo & City line, in the London Underground, nicknamed "The Drain"

People with the surname
Charles Drain (disambiguation), several people
Dorothy Drain (1909–1996), Australian journalist, columnist, war correspondent, editor and poet
Émile Drain (1890–1966), French actor and comedian
Geoffrey Drain (1918–1993), British trade union leader
Gershwin A. Drain (born 1949), American federal judge
Jim Drain (born 1975), American artist
Job Henry Charles Drain (1895–1975), English recipient of the Victoria Cross
Lauren Drain  (born 1985), American author
Robert D. Drain (born c. 1957), American judge
Sammy Drain (1945–2016), guitarist
Thomas Drain (born 1880), Scottish footballer
Tracy Drain, flight systems engineer at NASA