tube (to?ob, tyo?ob)n.1. a. A hollow cylinder, especially one that conveys a fluid or functions as a passage.b. An organic structure having the shape or function of a tube; a duct: a bronchial tube.2. A small flexible cylindrical container sealed at one end and having a screw cap at the other, for pigments, toothpaste, or other pastelike substances.3. Music The cylindrical part of a wind instrument.4. Electronics a. An electron tube.b. A vacuum tube.5. Botany The lower, cylindrical part of a gamopetalous corolla or a gamosepalous calyx.6. a. A tunnel.b. An underground railroad system, especially the one in London, England.7. The elongated space inside a wave when it is breaking.8. a. An inner tube.b. An inflatable tube or cushion made of rubber or plastic and used for recreational riding, as behind a motor boat or down a snow-covered slope.9. Informal a. Television: What’s on the tube?b. A television set.10. tubes Informal The fallopian tubes.v. tubed, tub·ing, tubes v.tr.1. To provide with a tube; insert a tube in.2. To place in or enclose in a tube.v.intr. To ride or float on an inflated tube for recreation.Idiom: down the tubes/tube Slang Into a state of failure or ruin: saw her plans go down the tubes.[French, from Old French, from Latin tubus.]American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.tube (tju?b) n1. a long hollow and typically cylindrical object, used for the passage of fluids or as a container2. a collapsible cylindrical container of soft metal or plastic closed with a cap, used to hold viscous liquids or pastes3. (Anatomy) anatomy a. short for Eustachian tube, Fallopian tubeb. any hollow cylindrical structure4. (Botany) botany a. the lower part of a gamopetalous corolla or gamosepalous calyx, below the lobesb. any other hollow structure in a plant5. (Railways) the tube a. Also called: the underground an underground railway system. US and Canadian equivalent: subway b. the tunnels through which the railway runsc. the train itselfd. (capital) trademark the London underground railway system6. (Electronics) electronics a. another name for valve3b. See electron tube, cathode-ray tube, television tube7. (Broadcasting) the tube slang a television set8. slang Brit a stupid or despicable person9. slang Austral a bottle or can of beer10. (Swimming, Water Sports & Surfing) surfing the cylindrical passage formed when a wave breaks and the crest tips forward11. an archaic word for telescopevb (tr) 12. to fit or supply with a tube or tubes13. to carry or convey in a tube14. to shape like a tube[C17: from Latin tubus] ?tubeless adj ?tube-like adjCollins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014tube (tub, tyub) n., v. tubed, tub?ing. n. 1. a hollow, usu. cylindrical body of metal, glass, rubber, etc., used esp. for conveying or containing liquids or gases. 2. a small collapsible cylinder of metal or plastic sealed at one end and having a capped opening at the other from which a semifluid substance, as paint or toothpaste, may be squeezed. 3. any hollow, cylindrical vessel or organ: the bronchial tubes. 4. the elongated lower part of a united sepal or corolla of a flower. 5. inner tube. 6. electron tube. 7. the tube, Informal. television. 8. a cylindrical garment without sleeves, pockets, or closures, usu. of stretch fabric, worn as a blouse, dress, skirt, etc. 9. the tubular tunnel in which an underground railroad runs. 10. the railroad itself. 11. Brit. subway (def. 1). 12. Surfing. the curled hollow formed on the underside of a cresting wave. v.t. 13. to furnish with a tube. 14. to convey or enclose in a tube. 15. to form into the shape of a tube; make tubular. v.i. 16. to float down a river on an inner tube. Idioms: down the tube(s), into a wasted or abandoned state. [1590?1600;