"When we say 'Aristotle,' we are using a word that means one or a series of definite descriptions of the type: 'the author of the Analytics,' or 'the founder of ontology,' and so forth" (What is an Author, 141).
A name serves purely as a designation or a signification. Simply put, the name is an artefact that allows us to hail the individual whom we recognise and he or she acknowledges. It is an indication, "a pure and simple reference...a gesture, a finger pointed at [the named individual]" (141).
An author's name, in addition to being purely a designation, reflects the works of the author as well. It transcends an indicative function and that is "the equivalent of a description" (141). It is this nature of an author's name--with dual roles in designation and description--that forms the basis of the so called author-function in Foucault's discussion.