c.1616, "pool or lake for irrigation or drinking water," a word originally brought by the Portuguese from India, ult. from Gujarati tankh "cistern, underground reservoir for water," Marathi tanken, or tanka "reservoir of water, tank." Perhaps from Skt. tadaga-m "pond, lake pool," and reinforced in later sense of "large artificial container for liquid" (1690) by Port. tanque "reservoir," from estancar "hold back a current of water," from V.L. *stanticare (see stanch). But others say the Port. word is the source of the Indian ones. Meaning "fuel container" is recorded from 1902. Military use originated 1915, partly as a code word, partly because they looked like benzene tanks. They were first used in action at Pozieres ridge, on the Western Front, Sept. 15, 1916. Slang meaning "detention cell" is from 1912. Tanker "ship for carrying oil or other liquid cargo," is first attested 1900. Tank top is 1968, from tank suit "one-piece bathing costume" (1920s), so called because it was worn in a swimming tank, or pool.

"to lose or fail," 1976, originaly in tennis jargon, but said there to be from boxing, from tank (n.) in some sense. Tanked "drunk" is from 1893.

a large container for liquids or gas
Example: a hot-water / cold-water tank

Arabic: صِهْريج Chinese (Simplified): 槽，箱（容器） Chinese (Traditional): 槽，箱(容器) Czech: rezervoár, nádrž Danish: beholder; -beholder Dutch: tank Estonian: paak Finnish: säiliö French: réservoir, cuve German: der Tank Greek: δεξαμενή, ντεπόζιτο Hungarian: tartály, tank Icelandic: geymir, tankur Indonesian: tangki Italian: serbatoio, tanica	Japanese: タンク Korean: (액체·가스 등의) 탱크 Latvian: cisterna; tvertne Lithuanian: cisterna, rezervuaras Norwegian: beholder, tank Polish: zbiornik Portuguese (Brazil): tanque, reservatório Portuguese (Portugal): depósito Romanian: rezervor, bazin Russian: бак Slovak: rezervoár, nádrž Slovenian: rezervoar Spanish: tanque, depósito Swedish: tank, behållare Turkish: depo, sarnıç, tank

a heavy steel-covered vehicle armed with guns

Arabic: دَبّابَه Chinese (Simplified): 坦克 Chinese (Traditional): 坦克 Czech: tank Danish: tank Dutch: tank Estonian: tank Finnish: panssarivaunu French: char d'assaut German: der Panzer Greek: άρμα μάχης, τανκ Hungarian: tank Icelandic: skriðdreki Indonesian: tank Italian: carro armato*	Korean: (군대) 탱크; 전차 Latvian: tanks Lithuanian: tankas Norwegian: stridsvogn, tank Polish: czołg Portuguese (Brazil): tanque de guerra Portuguese (Portugal): tanque Romanian: tanc Russian: танк Slovak: tank Slovenian: tank Spanish: tanque de guerra Swedish: stridsvagn Turkish: tank