/ Dictionary / Index R ratiocinate: Meaning and Definition of Find definitions for: ra•ti•oc•i•nate Pronunciation: (rash"ē-os'u-nāt", -ō'su-, rat"ē-), [key] — -nat•ed, -nat•ing. to reason; carry on a process of reasoning. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: ratiocinate (Thesaurus) ratio ratiocination 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