Of names, some are “proper,” and singular to one only thing, as “Peter,” “John,” “this man,” “this tree”; and some are “common” to many things, “man,” “horse,” “tree”; every of which, though but one name, is nevertheless the name of divers particular things; in respect of all which together, it is called an “universal”; there being nothing in the world universal but names; for the things named are every one of them individual and singular.

One universal name is imposed on many things, for their similitude in some quality, or other accident; and whereas a proper name bringeth to mind one thing only, universals recall any one of those many.