- English Grammar A2 Level - https://open.books4languages.com/english-a2-grammar -

Invariant Plural Nouns


Nouns refer to a person, place, thing, event, substance or quality.

Invariant nouns are nouns which have the same singular and plural form.


Invariant nouns do not follow the general plural formation rule, they are the same in singular and plural. When the noun has both singular and plural form the article is adapted to it, but if it has just a singular form, we don’t add -s to the end of the noun.

The most commonly used invariant plural nouns are: clothesfireworks, glassesgoggles, jeansoutskirtsscissors, series, thankstrousers

Adding a pair of before the noun makes these nouns singular, because we start to refer to them as one single entity.


  • I can’t fit into those clothes anymore. 
  • She was wearing a new pair of glasses.
  • These goggles cost a fortune!
  • We usually wear jeans. 
  • A pair of scissors is on the office desk.
  • This advertisement is about a new series.
  • My parents bought trousers for me and my sister. 


We use the invariant plural nouns in the same way as plural nouns.

They refer to some uncountable nouns or a single entity, something that is composed of more than one part (divided objects considered as one: scissorstrousersglasses…).


Invariant nouns are nouns with the same singular and plural forms, and we need to use the correct article to distinguish them. They don’t follow the general plural formation rule.

The most commonly used are: clothesfireworks, glasses, jeansscissorsthankstrousers

For example:
— “I bought a pair of jeans.” / “I bought two pairs of jeans.” = Jeans has the same form in both singular and plural.
— “My dad bought new trousers.” / “My dad bought a new trouser.” = Trousers can only exist in plural form.

Let’s revise this content within the {Form} section. Take a look at the {Example} section that shows its use within a context.