Sign

A phenomenon, the Indicator, exists as an indication of another phenomenon, the Indicated. The relationship is asymmetric: the Indicated is not necessarily a sign for the existence or presence of an Indicator. The Indicated can be a past, present, or future entity or eventuality. The relationship between Indicator and Indicated is not one of symbolization or iconicity. Rather the Indicator is an index of the Indicated. This is a sign of things to come.