/ Dictionary / Index T thresher: Meaning and Definition of Find definitions for: thresh•er Pronunciation: (thresh'ur), [key] — n. a person or thing that threshes. Also calleda large shark of the genus Alopias, esp. A. vulpinus, which threshes the water with its long tail to drive together the small fish on which it feeds. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: thresher (Thesaurus) thresh threshing machine Related Content Daily Word Quiz: placid Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language