/ Dictionary / Index E estrous cycle: Meaning and Definition of Find definitions for: es'trous cy"cle Pronunciation: [key] a series of physiological changes in sexual and other organs in female mammals, extending from one period of heat to the next, accompanied by behavioral changes indicating interest in mating. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. estrous estrus Related Content Daily Word Quiz: cetacean Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language