An early gas discharge tube used to demonstrate the principles of electrical glow discharge.

(sciences, engineering) A tube in the shape of a capital U, in certain applications having a semipermeable membrane in the middle.

A well in which a stainless steel tube is bored directly down into an aquifer

(physics) Any device in which a flow of electrons (or ions) through a gas acts as a source of light

The removable, light-emitting part of a fluorescent lamp

a type of butyrometer (used to estimate the proportion of butterfat in milk)

Alternative form of knob-and-tube

Of or pertaining to a type of electrical wiring consisting of insulated conductive copper wire affixed by porcelain hardware and protected in vulnerable areas by insulated cloth sleeving. Widely used in North America during the late 19th and early 20th centuries.

an empty cigarette consisting of a filter attached to a paper tube. / a tubular filter

A tube for conveying speech, especially from one room to another at a distance.