1 an instrument that measures air pressure and indicates changes in weather 气压计；晴雨表

2 something that indicates the state of sth (a situation, a feeling, etc) 能显示状态（形势、感受等）的事物: Results of local elections are often a barometer of the government's popularity. 地方选举的结果往往反映出政府受民众支持的程度。