/ Dictionary / Index T thumber: Meaning and Definition of Find definitions for: thumb•er Pronunciation: (thum'ur), [key] — n. Informal. a hitchhiker. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. thumb thumb glass 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