Common nouns can be subdivided according to what determiners they permit. Nouns such as those in column (3) of the table above can be made plural with no determiner (as in cars
), and they can take the indefinite article a/an
(as in a car
). Words that behave this way are typically regarded as referring to entities that are seen as individual, countable units, and hence they are known as count nouns
. Count nouns can be either concrete items (computer, book, house
, etc.) or abstract ideas (goal, belief, hope
Nouns that behave like the one in column (4) are called mass nouns (or non-count nouns). They typically refer to things that are viewed as a mass rather than individual units, or which have no precise shape or boundary. Mass nouns also can be either concrete (milk, wool, spaghetti, etc.) or abstract (happiness, communism, integrity). They cannot usually be made plural (*two wools), nor do they take the indefinite article (*a wool). If we want to count mass nouns, we must add a count noun to specify the quantity (two glasses of milk).