Definitions for "bellwether"
Keywords:  wether, flock, sheep, castrated, herd
A stock or bond that is widely believed to be an indicator of the overall markets...
A wether, or sheep, which leads the flock, with a bell on his neck.
Hence: A leader.
Much the same as a Biodiversity This term is normally used to imply that the diversity of plant and animal species should be maintained, and that extinction is undesirable, because you never know when a species might be useful. The idea can be extended beyond its biological reference to human cultures and languages. Their biodiversity might be important too.
Bellwether, a 1996 novel by Connie Willis, is a book that can fall into many genres, such as comedy, fairy tale, romance, and science fiction. The novel is broadly based on the unsettling concepts of human culture. It was nominated for the Nebula Award for Best Novel in 1997.
Keywords:  friday, par, black, below
below par Black Friday
someone who assumes leadership of a movement or activity