/ Dictionary / Index R ratiocination: Meaning and Definition of Find definitions for: ra•ti•oc•i•na•tion Pronunciation: (rash"ē-os"u-nā'shun, -ō"su-, rat"ē-), [key] — n. the process of logical reasoning. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: ratiocination (Thesaurus) ratiocinate ratiometer 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