N-COUNT
预言性事物；借以作出预测的事物
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...
民意测验并不能对选举结果进行可靠预测。
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.
通过观察孩子对新生儿到来的反应能很好预测在接下来的一年中他们会不会相处融洽。