#1 tube n. [tubing] conduit consisting of a long hollow object (usually cylindrical) used to hold and conduct objects or liquids or gases. wn
#2 tube n. [vacuum tube, thermionic vacuum tube, thermionic tube, electron tube, thermionic valve] electronic device consisting of a system of electrodes arranged in an evacuated glass or metal envelope. wn
#3 tube n. [pipe] a hollow cylindrical shape. wn
#4 tube v. provide with a tube or insert a tube into. wn
#5 tube v. convey in a tube; "inside Paris, they used to tube mail". wn
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