[tóng xué]
（在同一學校[班級]學習） be in the same school [class]; be a schoolmate of sb.
I studied in the same school with them for three years.
我和他們同過3年學。
（在一起學習的人） fellow student; schoolmate; classmate
（稱呼學生） comrade (a form of address used in speaking to a student)