Class

Definition: A group of students/people who learn together, or the time when you study.

Another definition: A group of things or people with similar traits

Examples:

I have English class at 9 a.m. – Class means a lesson, a time when you study.

My class is very friendly. – Class means a group of students studying together.

She comes from a middle-class family. – Class means a social group with similar traits.