xenon

UK: /ˈzɛnɒn/ US: /ˈzinɑn, ˈzɛnɑn/ ,(zē′non, zen′on)

WordReference Random House Learner's Dictionary of American English © 2025

xe•non /ˈzinɑn, ˈzɛnɑn/   n. [uncountable]

1. Chemistry a heavy, colorless, chemically inactive, gaslike element used for filling radio and television tubes.

WordReference Random House Unabridged Dictionary of American English © 2025

xe•non  (zē′non, zen′on), n. [Chem.]

1. Chemistry a heavy, colorless, chemically inactive, monatomic gaseous element used for filling radio, television, and luminescent tubes. Symbol: Xe;
   at. wt.: 131.30;
   at. no.: 54.

• Greek xénon, neuter of xénos strange (see -on²); name introduced by William Ramsay, the element's discoverer
• 1898

Collins Concise English Dictionary © HarperCollins Publishers::

xenon / ˈzɛnɒn/ noun

1. a colourless odourless element of the rare gas group, occurring in trace amounts in air; formerly considered inert it is now known to form compounds and is used in radio valves, stroboscopic and bactericidal lamps, and bubble chambers. Symbol: Xe; atomic no: 54; atomic wt: 131.29; valency: 0; density: 5.887 kg/m³; melting pt: –111.76°C; boiling pt: –108.0°C

Etymology: 19th Century: from Greek: something strange