/ Dictionary / Index R rational operation: Meaning and Definition of Find definitions for: ra'tional opera'tion Pronunciation: [key] any of the mathematical operations of addition, subtraction, multiplication, and division. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. rational number ratio test Related Content Daily Word Quiz: lyceum Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language