/ Dictionary / Index A Argun: Meaning and Definition of Find definitions for: Ar•gun Pronunciation: (är-gn'), [key] — n. Older Spelling. a river in NE Asia, forming part of the boundary between the Russian Federation and China. ab. 450 mi. (725 km) long. Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: argun (Thesaurus) argumentum Argus Related Content Daily Word Quiz: winsome Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language