indication

This term describes a pointer or a clue that allows an observer to infer a hidden state or a future event. It carries a nuance of indirectness; an indication is rarely a definitive proof, but rather a suggestive piece of evidence that requires interpretation. In medical contexts, the word takes on a more prescriptive meaning, referring to a specific symptom or condition that justifies the use of a particular medication or surgical procedure. This differs from the general sense of a sign by implying a necessary clinical action.