1
tube (n.)conduit consisting of a long hollow object (usually cylindrical) used to hold and conduct objects or liquids or gases;
tube (n.)electronic device consisting of a system of electrodes arranged in an evacuated glass or metal envelope;
Synonyms: vacuum tube / thermionic vacuum tube / thermionic tube / electron tube / thermionic valve
tube (n.)a hollow cylindrical shape;
tube (n.)(anatomy) any hollow cylindrical body structure;
Synonyms: tube-shaped structure
tube (n.)an electric railway operating below the surface of the ground (usually in a city);
in Paris the subway system is called the `metro' and in London it is called the `tube' or the `underground'
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