Backwash may refer to: Physical phenomena Backwash (physical phenomenon), also known as "swash", the backwards flow of air or water A mixture of beverage and saliva that has flowed back into a drinking vessel Backwash ileitis, the involvement of the terminal part of the ileum in ulcerative colitis, following the ascent of the condition from the rectum Backwashing (water treatment), the process of thoroughly cleaning a pool filter pump by reversing the flow of water through it with the dirt and rinse water going to waste Arts, entertainment, and media Backwash (album), a retrospective compilation by the group Talulah Gosh "Backwash" (The Wire), a 2003 episode of the HBO television series The Wire Backwash squeeze, a type of squeeze play in bridge Backxwash, Zambian-Canadian rapper and producer See also Mouthwash