indicator
/ˈɪndɪkeɪtə(r)/noun
1
- a thing, especially a trend or fact, that indicates the state or level of something指示物, 标志：
car ownership is frequently used as an indicator of affluence.
拥有小汽车常常被用来表示富裕。
2
- a device providing specific information on the state or condition of something, in particular指示器, 显示器, 装置, 尤指：
2.1
- usu. with modifier a gauge or meter of a specified kind…计, …仪, …表：
a speed indicator.
示速器。
2.2
- Brit. a board or screen in a railway station, airport, etc. giving current information〈英〉（火车站、飞机场等的）信息显示板, 信息显示屏。
2.3
- a flashing light or (formerly) other device on a vehicle to show that it is about to change lanes or turn（车辆上的）方向灯; （旧时的）变向（或变道）指示器。
3
- Chemistry a compound which changes colour at a specific pH value or in the presence of a particular substance, and can be used to monitor acidity, alkalinity, or the progress of a reaction【化】指示剂。
4
- （亦作indicator species）an animal or plant species which can be used to infer conditions in a particular habitat（用来推断某生境的植物）指示（物）种。