/ Dictionary / Index H hyoscyamus: Meaning and Definition of Find definitions for: hy•os•cy•a•mus Pronunciation: (hī"u-sī'u-mus), [key] — n. the dried leaves, with or without the tops, of the henbane, Hyoscyamus niger, containing the alkaloids hyoscyamine and scopolamine, used in medicine. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: hyoscyamus (Thesaurus) hyoscyamine hyp Related Content Daily Word Quiz: arid Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language