/bel"wedh'euhr/ , n.
1. a wether or other male sheep that leads the flock, usually bearing a bell.
2. a person or thing that assumes the leadership or forefront, as of a profession or industry: Paris is a bellwether of the fashion industry.
3. a person or thing that shows the existence or direction of a trend; index.
4. a person who leads a mob, mutiny, conspiracy, or the like; ringleader.
[ 1400-50; late ME; see BELL 1 , WETHER ]
Syn. 2. leader, pacesetter, frontrunner, trailblazer.