From Teflpedia

A referent (/ˈrefərənt/) is something that is the object of a reference.

A referent may be an exophoric referent, i.e. outside of the text. Or it could be an endophoric referent; an antecedent or anaphoric referent (before in the text), or a cataphoric referent or a postcedent, i.e. after in a text.