Common Nouns
Common nouns are ordinary category names for people, animals, places, things, and ideas. They contrast with proper nouns, which identify specific named entities and are conventionally capitalized.
A common noun names a class or category rather than a specific named entity; proper nouns identify specific names and normally begin with a capital letter.
Key details
Important caveats
Scope Boundary
Capitalization can change with function and context, so the same lexical item may be common in one use and part of a proper name in another.
Further guidance
Application
Treat ordinary category names such as “teacher,” “city,” and “book” as common nouns; capitalize only when another rule requires it, such as sentence position or a proper-name use.
Core Rule
A common noun refers to a class or category of people, animals, places, things, or ideas, unlike a proper noun that names a specific entity.
Practical Application
Classify the noun by whether it names a general class or a specific official name. Keep common nouns lowercase unless another rule—such as sentence position or a style-specific title rule—requires capitalization.
Reader Check
If you replace the word with another member of the same class, is it still a general category rather than a unique official name?
Worked Example
In “The university hired a new professor,” both nouns are common. In “Northbridge University hired Professor Chen,” the official name and personal title/name follow proper-name capitalization rules.
Sources and evidence
Sources are shown with the role they play in this guide. Historical or style-sensitive claims are kept within the evidence boundary described above.
- Nouns — English Grammar Today (opens in a new tab)Cambridge University Press & Assessment · Grammar evidence that common nouns refer to classes/categories and contrast with capitalized proper nouns.