- a wether or other male sheep that leads the flock, usually bearing a bell.
- a person or thing that assumes the leadership or forefront, as of a profession or industry: Paris is a bellwether of the fashion industry.
- a person or thing that shows the existence or direction of a trend; index.
- a person who leads a mob, mutiny, conspiracy, or the like; ringleader.
mid-15c., from bell + wether; the lead sheep (on whose neck a bell was hung) of a domesticated flock; used earlier in the figurative sense of "chief, leader" (early 15c.). (http://dictionary.reference.com/browse/bellwether)
"This inventive take on the traditional family novel nods at bellwethers of the genre but feels as if it could only have been written yesterday."
- "Briefly Noted", 3 August 2015 The New Yorker (http://www.newyorker.com/magazine/2015/08/03/briefly-noted-among-the-ten-thousand-things)