For Fellow Students Meaning?

a student in the same school, university, college, etc as you.

How do you refer to a fellow student?

A person who attended school with the subject. Fellow students is also correct and grammatical. Worth mentioning that "schoolmate" implies they attend the same school, while "fellow student" includes those who attend a different school.

What does fellow classmate mean?

fellow classmate or classmate

Your classmate is a person in your class in school, college, or university. “I met Minh when he was my classmate in English class.” To say 'fellow classmate' is redundant because the meaning of classmate already includes the sense that this person is a fellow member of your class.