A common noun is a non-specific name for people, places. things, events.

Non-specific means it does not refer to a particular person, place, thing, or event. It can refer to anyone/anything within a class or group. A common noun starts with a lower case letter.

Examples:

1. boy — can be any boy A proper noun could be “Samuel”.
2. city — can be any city A proper noun could be “New York City”.
3. teacher — can be any teacher A proper noun could be “Miss Sandoval”.
4. cat — can be any cat A proper noun could be “Garfield”.