* Common nouns are general names for people, places, or things. They are not capitalized unless they are part of a proper noun.
* Command nouns are nouns that are used to give a command, like "Halt!" or "Attention!".
Examples of how "ranger" is used:
* "The ranger guided us through the forest." (common noun)
* "The Rangers are playing the Red Wings tonight." (proper noun, specifically a team name)
Let me know if you have any more questions about parts of speech!