Definition of "tube" []

• A hollow cylinder, especially one that conveys a fluid or functions as a passage. (noun)
• An organic structure having the shape or function of a tube; a duct: a bronchial tube. (noun)
• A small flexible cylindrical container sealed at one end and having a screw cap at the other, for pigments, toothpaste, or other pastelike substances. (noun)
• Music The cylindrical part of a wind instrument. (noun)
• Electronics An electron tube. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "When an ovum is matured, it escapes from the ovary into the narrow tube referred to, called the _Fallopian tube_, and passes down into the cavity of the uterus."
• "It is passed down a tube that we call the _food tube_."
• "The _middle ear_, it will be seen, is a drum with its stretched membrane like any other drum, and it too has a communication with the exterior air through a tube, the _Eustachian tube_, which leads from the drum into the back part of the throat."