Here's why:
* Nouns are words that name people, places, things, or ideas. "Class" fits into the "things" or "ideas" category. It refers to a group of students, a category of objects, or a level of quality.
* Nouns can be proper or common. "Class" is a common noun, meaning it refers to a general category and isn't capitalized.
* Nouns can be concrete or abstract. "Class" is more abstract than concrete. We can't physically touch a "class," but we can experience it through shared learning or observation.
Examples:
* A class of students: Here, "class" refers to a group of people.
* The upper class: Here, "class" refers to a social category.
* A class of cars: Here, "class" refers to a category of objects.
To summarize: "Class" is a noun, but it does not refer to a person. It refers to a category, a group, or a level of quality.