a hollow cylinder or pipe of metal, glass, rubber, etc., usually long in proportion to its diameter, used for conveying fluids, etc.
an instrument, part, organ, etc. resembling a tube: bronchial tubes, eustachian tubes
a fallopian tube: usually used in pl.
a rubber casing inflated with air and used, esp. formerly, with an outer casing to form an automotive tire
a cylindrical container made of thin, pliable metal, plastic, etc., fitted at one end with a screw cap, and used for holding pastes or semiliquids, which can be squeezed out
Bot. the lower, united part of a gamopetalous corolla or a gamosepalous calyx
Elec. the tubular space bounded by the lines of electric or magnetic force passing through every point on a closed curve on the outside of a charged body