A classmate is a student who is member of the same class, in any of its meanings (a course, a lesson, a graduating year).
In psychology, a classmate is a person who is enrolled in the same class as another person. Classmates typically share the same teacher and are often working on the same assignments and projects. They may also interact with each other outside of class, such as during study groups or social activities. Classmates are often considered to be a social group, and their relationships with each other can have an impact on their academic and personal development.