/ Dictionary / Index L Law of the Medes and the Persians: Meaning and Definition of Find definitions for: Law' of the Medes' and the Per'sians Pronunciation: [key] unalterable law. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. law of the mean law of thermodynamics Related Content Daily Word Quiz: hale Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language