Proper and common nouns differ in one way: capitalization. Is it a cat or is it Nibbles? Is it a country or is it the United Kingdom?
Any person, place, thing or idea that is not capitalized is called a “common noun.” Be careful to not lump “he,” “she” and “it” into this category; these words are pronouns and not nouns at all.
“The cat didn’t come home until morning.”
“We visited a theme park when we went on vacation.”
“The girl was talking to my aunt about a racehorse.”
“That country is quite far from where I live.”
“The governor was narrowly elected to a second term.”
“We are celebrating the holiday with a pizza.”
When a specific person, place, thing or idea is capitalized, it is called “proper.” This includes names, titles and brands, such as “Senator,” “Chevrolet” or “Bob.”
“Nibbles didn’t come home until morning.”
“We visited Penny’s Pickle Paradise when we went on vacation.”
“Tina was talking to Aunt Betty about Magic Super Bullet.”
“New Zealand is quite far from where I live.”
“Governor Chickenhooper was narrowly elected to a second term.”
“We are celebrating Garlic Appreciation Day with a Garlic Explosion pizza.”