A countable noun or count noun is one which represents an individual item, such as "book" or "table". Count nouns can be used in the singular or the plural - "one book", "many books". An uncountable noun or mass noun is one which represents something that doesn't divide nicely into individual items, such as "sand", "oxygen" or "happiness".
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.