a pipe, tube or canal which carries gas or liquid from one place to another
a vessel for conveying lymph or glandular secretions such as tears or bile
a tube or elongated cavity (such as a xylem vessel) for conveying water, sap, or air
a layer (as in the atmosphere or the ocean) which occurs under usually abnormal conditions and in which radio or sound waves are confined to a restricted path
an enclosure or channel for electrical cable runs, telephone cables, or other conductors
to enclose in a duct
to channel something (such as a gas) or propagate something (such as radio waves) through a duct or series of ducts
An adjustable gate or valve used to control the flow of water through a sluice.
Anything that controls or limits an outpouring of people, emotion etc.