Bellwether

Derives from 'bell + wether', where a 'wether' was originally a castrated ram that wore a bell around its neck to make the flock follow it, in and out of the pen or wherever. The current usage and meaning of 'bellwether' is a leader or a trendsetter as, for example, in a bellwether stock, or a bellwether share that is usually a blue-chip stock or share that is regarded as a market leader in its particular sector of the stock market. Although there is an element of forecasting in this current usage, please note that 'bellwether' has nothing whatsoever to do with the 'weather'. Its current figurative usage dates from as long ago as the late 1400s. Before this, the literal meaning of 'bellwether', as already mentioned, was the leading sheep in a flock because of the bell around its neck. The word 'wether' on its own is also very old, dating from before 1150 and means a male sheep, usually a castrated ram. Such a sheep then became a 'bellwether' if was chosen to receive its bell and become the leader of the flock.