/ Dictionary / Index G guaiacum: Meaning and Definition of Find definitions for: guai•a•cum Pronunciation: (gwī'u-kum), [key] — n. any of several tropical American trees or shrubs belonging to the genus Guaiacum of the caltrop family; lignum vitae. the hard, heavy wood of such a tree; guaiac. resin obtained from such a tree; guaiac. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: guaiacum (Thesaurus) guaiacol Guaira Related Content Daily Word Quiz: neologism Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language