{i} male sheep that leads a flock (usually wears a bell); leader (Slang); talker, chatterer; stock or bond that is an indicator of the entire market's condition (Finance)
a stock on the market that tells you which direction the market is going in or is likely to go in Comes from the concept of the leading sheep in a flock, the one that wears the bell
If you describe something as a bellwether, you mean that it is an indication of the way a situation is changing. For decades the company was the bellwether of the British economy IBM is considered the bellwether stock on Wall Street
A leading indicator of trends A bellwether stock is a stock which is used to gauge the performance of the market in general General Motors is an example of bellwether stock in the past Hence the saying "What's good for GM is good for America"