I was looking for the word "batchmate" (entered the same year as you/in the same school grade, i.e. in between 先輩 and 後輩), and found some answers (1,2) on this site that gives 同級生 as a translation to "classmate". Can this word also be used for students not in the same class but in the same grade? For example, students in a club of the same grade but in different classes.
For context, the sentence I am trying to build is
I was laughed at by my seniors, my batchmates, and even by my juniors.
This is in context of club activities.
The answers on this site linked above translate 同級生 as "classmate", and so do some Japanese-English dictionaries. That surprised me because of how breaking up the kanji would literally give "same-grade-students". Can 同級生 also be used in the example above?
Or... does the Japanese concept of "classmates" extend beyond classes and include everyone in the same grade? I have no idea.