1. Capitalization: The most reliable indicator is capitalization. Proper nouns are always capitalized, while common nouns are not.
* Example: "The United States has a president." (United States is a proper noun)
* Example: "The country has a president." (country is a common noun)
2. Context: Sometimes, even without capitalization, the context can give you a clue.
* Example: "We saw a monument that commemorated a famous battle." (Monument and Battle are probably proper nouns based on the surrounding words)
3. Specific References: Proper nouns often refer to specific people, places, things, or organizations. Common nouns refer to general categories.
* Example: "The dog barked at the mailman." (Dog is common, Mailman is likely a proper noun since it refers to a specific individual)
4. Titles: Titles of books, movies, plays, songs, etc., are often proper nouns.
* Example: "I watched the movie Avatar."
5. Places and Organizations: Proper nouns are commonly used for cities, countries, companies, schools, etc.
* Example: "I live in London, and I work for Google."
Things to Note:
* Abbreviations: Proper nouns can be abbreviated, which can be confusing. (e.g., "UN" for United Nations)
* Foreign Languages: Capitalization rules vary in different languages, so proper nouns may not always be capitalized as they are in English.
* Exceptions: There are some exceptions, and some words can function as both proper and common nouns depending on the context.
Let me know if you'd like more examples!