SEMANTICS: a noun which refers to something without clear boundaries
or individual members, like milk and gold. Also called mass
term. In English, mass nouns cannot be pluralized (cf. *milks) and
cannot be used with the indefinite article (cf. *a milk) or with
numerals (cf. *one milk). Mass nouns like cattle and
furniture are sometimes called collective nouns because they refer
to a collection of individuals, but not to any one individual. The opposite
of a mass noun is called a count noun.