indicator

英文解釋：

名詞 indicator:

1. a number or ratio (a value on a scale of measurement) derived from a series of observed facts; can reveal relative changes as a function of time
   同義詞：index, index number, indicant
2. a signal for attracting attention
3. a device for showing the operating condition of some system
4. (chemistry) a substance that changes color to indicate the presence of some ion or substance; can be used to indicate the completion of a chemical reaction or (in medicine) to test for a particular reaction

中英例句：

1. He talks about economic growth as a great indicator for freedom, I agree with him.
   他論及經濟成長是自由的一個有力的顯示器，我同意。
2. An indicator or a sighting apparatus on a plane table, used in angular measurement.
   旋標裝置飛機控制板上的指示器或觀測儀，用來測量角度
3. A hand-held, button-activated input device that when rolled along a flat surface directs an indicator to move correspondingly about a computer screen, allowing the operator to move the indicator freely, as to select operations or manipulate text or graphics.
   滑鼠一種手用的、用按扭控制的輸入設備，當在平台上滑動時可以相應地移動計算機螢幕上的指示箭頭，使得操作者可以隨意控制指示箭頭，由此來選擇項目、控制內容或作圖