Word for today is



  1.  a person or thing that shows the existence or direction of a trend
  2.  a wether or other male sheep that leads the flock, usually bearing a bell.
  3.  a person or thing that assumes the leadership or forefront, as of profession or industry.
  4.  a person who leads a mob, mutiny, conspiracy, or the like, ringleader.

The word was derived from “wether” meaning ” a castrated male sheep”.