bellwether

1. N-COUNT If you describe something as a bellwether, you mean that it is an indication of the way a situation is changing. 征兆; 风向标[美国英语] [journalism] [usu sing, oft N n]

The Methodist church is viewed as a bellwether of U.S. attitudes in large part. 卫理公会派教堂在很大程度上被认为是美国立场的风向标。

IBM is considered the bellwether stock on Wall Street. IBM的股票行情被认为是华尔街股市的风向标。