Plural noun is defined as a noun that is generally used only in the plural form. Most frequently, therefore, plurals are applied to indicate two or more of something, even though they may also indicate fractional, zero or also negative amounts.
Plural noun = a noun that has been multiplied (a noun is a person, place, or thing.) For example, "car" is a regular noun. If it were a plural noun, it'd be "cars." A plural noun used in a sentence: "The cars drove a long way."