…a long, hollow cylinder of metal, plastic, glass, etc. for holding or transporting something, chiefly liquids or gases…
…a natural tunnel within a solidified lava flow, formerly occupied by flowing molten lava…
…a thin glass tube closed at one end, used to hold small amounts of material for laboratory testing or experiments…
…(in an echinoderm) each of a large number of small flexible hollow appendages protruding through the ambulacra, used either for locomotion or for collecting food and operated by hydraulic pressure within the water-vascular system…
…a round cake pan with a hollow, cone-shaped center, used for baking ring-shaped cakes…
…a well consisting of an iron pipe with a solid steel point and lateral perforations near the end, which is driven into the earth until a water-bearing stratum is reached, when a suction pump is applied to the upper end…
…a marine bristle worm, especially a fan worm, which lives in a tube made from sand particles or in a calcareous tube that it secretes…
…the calcareous or sandy tube of some sedentary marine worms, such as fan worms…
…a gas-discharge tube used, especially in photography, to provide an electronic flash when a current is suddenly passed through it…
…(in an embryo) a hollow structure from which the brain and spinal cord form. Defects in its development can result in congenital abnormalities such as spina bifida…
…an open-ended right-angled tube pointing in opposition to the flow of a fluid and used to measure pressure…
…a hollow tube which develops from a pollen grain when deposited on the stigma of a flower. It penetrates the style and conveys the male gametes to the ovule…
…a series of sieve tube elements placed end to end to form a continuous tube…
…a sealed glass tube containing a near-vacuum which allows the free passage of electric current…
…a tube, usually of clear flexible plastic with lateral perforations, for draining a wound, abscess, etc.…
…an evacuated or gas-filled tube in which a current of electrons flows between electrodes…
…a sealed tube of glass or quartz with a central constriction, filled with vapour for the production of a luminous electrical discharge…
…the cathode ray tube of a television set designed for the reproduction of television pictures…
…a pipe for conveying a person’s voice from one room or building to another…
…a tube passed into the stomach via the gullet for cleansing or emptying it or for introducing food…
…a tube in a submarine or other ship from which torpedoes are fired by the use of compressed air or an explosive charge…
…a device for generating X-rays by accelerating electrons to high energies and causing them to strike a metal target from which the X-rays are emitted…
…a tube containing charged electrodes and filled with a gas in which ionization is induced by an electric field. The gas molecules emit light as they return to the ground state…
…a narrow passage leading from the pharynx to the cavity of the middle ear, permitting the equalization of pressure on each side of the eardrum…
…a tube fitted to a camera between the body and lens to shorten the distance of closest focus of an object so that close-up pictures can be taken…
…(in a female mammal) either of a pair of tubes along which eggs travel from the ovaries to the uterus…
