Irregular Plural Nouns

English Grammar A1 Level: Nouns refer to a person, place, thing, event, substance or quality. Plural form  is used to indicate that there is more than one person, animal, place  or thing. Some nouns don’t follow the rules, they’re irregular, so their plural is formed differently. https://open.books4languages.com/english-a1-grammar/chapter/irregular-plural-nouns