A common noun is a word that names people, places, things, or ideas. They are not the names of a single person, place or thing.

A common noun begins with a lowercase letter unless it is at the beginning of a sentence.

For example:-

People:-

man, girl, boy, mother, father, child, person, teacher, student

Animals:-

cat, dog, fish, ant, snake

Things:-

book, table, chair, phone

Places:-

school, city, building, shop

Ideas:-

love, hate, idea, pride