classmate
n. countable A1 Beginner US //ˈkɫæsˌmeɪt// UK //klˈɑːsmeɪt// class·mate
n. someone who is in the same class as you at school or university.
n. a member of the same class at an educational institution.
I am working on a project with my classmate.
After the lecture, she met a classmate in the library to compare their notes for the upcoming exam.
Maintaining connections with a former classmate can prove professionally advantageous, as shared educational backgrounds often foster a unique level of mutual trust and understanding in later career stages.
From class + mate.
Usage
Commonly used in both singular and plural forms; often preceded by a possessive adjective like 'my' or 'his'.