Nouns can be either countable or uncountable. Countable nouns (or count nouns) are those that refer to something that can be counted.
A smaller number of nouns do not typically refer to things that can be counted and so they do not regularly have a plural form: these are known as uncountable nouns
Collective nouns refer to groups of people or things, e.g. audience, family, government, team, jury. Collective nouns can usually be treated as singular or plural, with either a singular or plural verb.