" A function indicates a relationship in prospect, and so belongs to a family of concepts. Relationship, as in related; relationship, as in connected, corresponding to or caused by, united or bound together; relationship, as in linked or yoked, coupled or conjoined, associated or allied. Relationship, as in dependent, indeed, relationship, as in function of,
at which point the moving conceptual point may be seen revolving around the perimeter of a circle. "

― David Berlinski