Before revision: In philosophy of language , an extensional context (or transparent context) is a syntactic environment in which a sub-sentential expression e can be replaced by an expression with the same extension and without affecting the truth-value of the sentence as a whole.
After revision: In philosophy of language —any of several fields of study that treat the use of signs — for example, in linguistics, logic, mathematics, semantics, semiotics, and an extensional context (or transparent context) is a syntactic environment in which a sub-sentential expression e can be replaced by an expression with the same extension and without affecting the truth-value of the sentence as a whole.