/ Dictionary / Index P perfect square: Meaning and Definition of Find definitions for: per'fect square' Pronunciation: [key] — Math. Math. a rational number that is equal to the square of another rational number. a polynomial that is the square of another polynomial. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. perfect rhyme perfect stage Related Content Daily Word Quiz: deleterious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language