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