a linguistic form that refers to an individual directly -- that is, it names an individual rather than a category. The term proper name is also used; we will consider these two terms to be synonymous. Example: Bill Croft refers to a particular individual. Note that being a proper noun is a function of a form; one can use the form Bill Croft as a common noun -- for example, to refer to a category of all persons named Bill Croft. (Section 3.1.1)