Is common the opposite of proper nouns?

Not exactly. While they are opposites in a way, the relationship is more nuanced. Here's a breakdown:

* Proper Nouns: Specific names of people, places, things, or organizations (e.g., John, London, Eiffel Tower, Google). They are always capitalized.

* Common Nouns: General categories of things (e.g., person, city, building, company). They are not capitalized unless they start a sentence.

Here's how they relate:

* Opposite in Specificity: Proper nouns are specific instances of something, while common nouns are general classifications.

* Not True Opposites: You can have a common noun that refers to a specific thing (e.g., "the mountain" referring to a specific mountain). You can also have a proper noun that becomes a common noun (e.g., "kleenex" now refers to any tissue).

Think of it this way:

* Common Noun: A big box labeled "Cars".

* Proper Noun: A specific car within that box labeled "Ford Mustang".

They are different levels of categorization. Common nouns are the broad categories, and proper nouns are the specific examples within those categories.