(n): a passage (a pipe or tunnel) through which water or electric wires can pass
(n): electronic device consisting of a system of electrodes arranged in an evacuated glass or metal envelope
(n): a device that accomplishes its purpose electronically
(n): a hollow cylindrical shape
(n): a surface generated by rotating a parallel line around a fixed line
(n): (anatomy) any hollow cylindrical body structure
(n): a particular complex anatomical part of a living thing
(n): an electric railway operating below the surface of the ground (usually in a city)
(n): line that is the commercial organization responsible for operating a system of transportation for trains that pull passengers or freight
(v): provide with a tube or insert a tube into
(v): give something useful or necessary to
(v): convey in a tube
(v): take something or somebody with oneself somewhere
(v): ride or float on an inflated tube
(v): be carried or travel on or in a vehicle
(v): place or enclose in a tube
(v): enclose or enfold completely with or as if with a covering
An endotracheal tube, a breathing tube placed down someone's throat into their windpipe.
Also, to put one in a patient. "He couldn't keep up his sats, so we had to tube him."