/ Dictionary / Index H H.C.M.: Meaning and Definition of Find definitions for: H.C.M. Pronunciation: [key] His Catholic Majesty; Her Catholic Majesty. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. H chain H. Con. Res. Related Content Daily Word Quiz: simian Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language