 Both count and mass nouns admit the definite article. There are sentence forms with a mass noun prefaced by the definite article, such as “Socrates drank the hemlock in that cup,” “Bob just wrote your name in the snow over there.” These sentences, if true, will be cases of definite reference of mass expressions, in that they pick out an actual concrete referent. Both mass and count nouns admit definite reference. But, it is controversial whether definite reference to stuff is singular reference.