a. A large, often metallic container for holding or storing liquids or gases.
b. The amount that this container can hold: buy a tank of gas.
2. A usually artificial pool, pond, reservoir, or cistern, especially one used to hold water for drinking or for irrigation.
3. A usually glass-walled container in which live fish, reptiles, or other animals are kept.
4. An enclosed, heavily armored combat vehicle that is armed with cannon and machine guns and moves on continuous tracks.
5. A tank top.
6. Slang A jail or jail cell.
v. tanked, tank·ing, tanks
To place, store, or process in a tank.
Informal To suffer a sudden decline or failure: The stock market tanked yesterday.
1. Slang To drink to the point of intoxication.
2. To fill the tank of a motor vehicle with gasoline.
in the tank
1. In reserve: a runner who didn't have enough in the tank to hold the lead.
2. In a state of decline or failure: Stocks have been in the tank for months.
3. Enthusiastically partial; strongly favoring: a reporter accused of being in the tank for a candidate.
[Partly from an Indic source such as Gujarati ṭāṃkhī, cistern, and ṭāṃkhī,ṃ, reservoir, or Marathi ṭāṃkeṃ, cistern, reservoir (all from Prakrit ṭaṅka, ditch, reservoir, of unknown origin) and partly from Portuguese tanque, reservoir (variant of estanque, from estancar, to dam up, from Vulgar Latin *stanticāre; see STANCH1). Noun, sense 4, from the fact that in WWI the British army tried to conceal the development and transport of such armored vehicles by referring to them as water tanks in documents and communications.]
tankful′ (-fl′) n.
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2020 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.