classmate

noun2

1. •
   A student who is in the same class at school.

   • Danny and I have been classmates for five years, but I've never spoken to him outside of lessons.
2. •
   A member of a different sort of class, such as locomotives etc.

   • The Class 87 is the only main line-certified member of the fleet left in the UK, although there are 21 classmates in use overseas [...] — 2019