Converse (semantics)
In linguistics, converses or relational antonyms are pairs of words that refer to a relationship from opposite points of view, such as parent/child or borrow/lend. The relationship between such words is called a converse relation. Converses can be understood as a pair of words where one word implies a relationship between two objects, while the other implies the existence of the same relationship when the objects are reversed. Converses are sometimes referred to as complementary antonyms because an "either/or" relationship is present between them. One exists only because the other exists.