/ Dictionary / Index M Mill Valley: Meaning and Definition of Find definitions for: Mill' Val'ley Pronunciation: [key] a town in W California, NW of San Francisco. 12,967. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. millstream Millville Related Content Daily Word Quiz: clairvoyant Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language