Generic nouns are nouns which are part of a generic statement. They’re different from definite nouns (e.g. the book) and indefinite nouns (e.g. a book) in that the sentence they’re must be a blanket statement or question. Generic nouns can be singular or plural. Make sure the verb which is modifying the generic noun agrees with the generic noun (e.g. the gang of boys was, the gangs of boys were)
The opposite of generic nouns is collective nouns (see Collective Nouns). If it refers to a specific group, it’s not generic.
The pride of lions are cats.
Pride is a collective noun which is modifying lions; cats is generic.
Cats are animals.
Both cat and animals are generic nouns.
A cat is an animal.
Despite the indefinite article, this noun is still generic because we’re not talking about a specific cat.
The cat has been an integral part of civilization.
While there is a definite article in front of cat, this sentence refers to cats in a general sense, so it’s a generic noun.
Civilization has always included cats.