How can you identify common and proper nouns?

Answer 1

A common noun is a word for any person, place, or thing.

A proper noun is the name of a specific person, place, thing, or a title. A proper noun is always capitalized. Examples:

• a person: common noun, boy; proper noun Oliver Twist
• a place: common noun, city; proper noun, New York City
• a thing: common noun, soda or soft drink; proper noun, Coca Cola (or Coke)
• a title: common noun, president or book; proper noun, President of the United States or "War and Peace" by Leo Tolstoy

That being said, you can't rely solely on a capitalized word being a proper noun, both individuals and professionals sometimes capitalize incorrectly or fail to capitalize when necessary. Many words can be both a common noun and a proper noun and it's best to know which is which. Examples:

I have an apple in my lunch. Fiona Apple is an American singer.
We went to the lake for a week this summer. Here is a map of Lake Michigan.
We can paint the room cream and yellow. We have some Ben & Jerry's Ice Cream.
My secretary can make an appointment for you. Ray Mabus is the US Secretary of the Navy.

Answer 2

Common nouns refer to general people, places, things, or ideas (e.g. boy, city, car), while proper nouns refer to specific names of people, places, things, or ideas (e.g. John, Paris, Toyota). Common nouns are not capitalized unless they start a sentence, whereas proper nouns are always capitalized.