* Adjective: Describing something related to the United States of America.
* Example: "She has American citizenship."
* Noun: A person from the United States of America.
* Example: "The American tourists visited the Eiffel Tower."
* Proper noun: When referring to the United States of America itself.
* Example: "America is a large country."
It's important to look at the context of the sentence to determine which part of speech is being used.