/ Dictionary / Index X xenon: Meaning and Definition of Find definitions for: xe•non Pronunciation: (zē'non, zen'on), [key] — n. Chem. 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. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: xenon (Thesaurus) xenomorphic xenon arc Related Content Daily Word Quiz: immense Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language