/thresh"euhr/ , n.
1. a person or thing that threshes.
2. Also, thrasher . Also called thresher shark . a 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.
[ 1350-1400; ME thressher. See THRESH, -ER 1 ]