These name specific people, places, things, or ideas.
Britney, Paris, Rover, Nike
Since these nouns are naming specific things, they begin with a capital letter.
Sometimes, they contain two or more important words.
Britney Spears, Central Park Zoo, Pacific Ocean
If this is the case, both important words are capitalized, and the whole thing is still considered to be one proper noun even though it's made up of more than one word. How about that?
Common nouns are your run-of-the-mill, generic nouns. They name people, places, things or ideas that are not specific.
woman, city, dog, shoe
Since these nouns are not naming anything specific, they do not need to start with a capital letter unless they begin a sentence.
Psst! If you need a refresher on nouns, see the nouns page.
Every proper noun has a common noun equivalent, but not every common noun has a proper noun equivalent.
For example, dust is only a common noun. There is no specific kind of dust, so it's just common.
Both of these kinds of nouns can perform many jobs in sentences (subject, direct object, indirect object, object of the preposition, predicate nominative).
Here are some examples of all of these noun jobs.
Subject: The students happily studied grammar.
Direct Object: The students happily studied grammar.
Indirect Object: They taught their friends grammar.
Object of the Preposition: Their friends smiled with glee.
Predicate Nominative: They were grammar champions!
Sentence diagramming is an effective and fun way to learn grammar, so what are you waiting for? Try it!