A kind of phytoclast consisting of micrometre-scale tubes with a banded internal ornamentation, known from terrestrial/freshwater settings from the early Silurian onwards.

A very cold dry-climate vegetation type consisting of mostly treeless open herbaceous vegetation, widespread during Pleistocene times at mid-latitudes of Eurasia and during some phases in North America.

(US, colloquial) Time spent by an infant in the prone position while awake and supervised, supposed to reduce the risk of skull deformation from spending too much time supine.

present participle of tumble to

(electronics, becoming dated) In a television set, before the development of LED screens, the cathode ray tube which produced moving images on its surface.

Alternative form of travelling-wave tube

(electronics) A type of vacuum tube that detects electromagnetic radiation in the range from ultraviolet to infrared, including the visible spectrum, and them amplifies the detection induced current into an output signal

(electronics) A type of vacuum tube which amplifies electromagnetic signals, where the electron gun fires down the tube with an unmodulated electron beam, that passes through an interaction array, where the EM-signal is fed, which interacts with the electron beam, bunching the electrons, and transferring power to the signal.

plural of tube well

(video games, slang) A very overpowered firearm, especially a grenade launcher.