A noun is called plural if it denotes more than one person, thing, place, etc.
- Two women are busy drawing water from the well.
- Some people were standing on the platform.
- Not all students are obedient.
- Can you answer all the questions correctly?
- Wolves began to howl when the night fell.
The highlighted words in the above sentences indicate nouns that are more than one in number. They are, therefore, plural nouns.