N-COUNT
預言性事物；借以作出預測的事物
You can refer to something that helps you predict something that will happen in the future as a predictor of that thing.
例句
Opinion polls are an unreliable predictor of election outcomes...
民意測驗并不能對選舉結果進行可靠預測。
The child's reaction to the arrival of the new baby was a very good predictor of how they would get on during the year that followed.
通過觀察孩子對新生兒到來的反應能很好預測在接下來的一年中他們會不會相處融洽。