/ Dictionary / Index A allochthon: Meaning and Definition of Find definitions for: al•loch•thon Pronunciation: (u-lok'thun, -thon), [key] — n. Geol. a geological formation not formed in the region where found and moved to its present location by tectonic forces. Cf. autochthon (def. 3). Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. allochromatic allochthonous Related Content Daily Word Quiz: panacea Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language