同学

同学 (tóngxué) is the Chinese word for 'classmate' or 'schoolmate' — anyone who studies (or has studied) at the same school or in the same class as you. Literally 'same-study,' it covers primary school through graduate school, and the bond it implies is stronger than the English 'classmate': adults still refer to people they met in school decades earlier as 老同学 'old classmates.' Two extra uses to know: first, teachers in China call on students with [name]同学 or just 同学们 'class / everyone' — it's the standard schoolroom address.

Second, on the street a shopkeeper or a stranger may call a young person 同学 as a friendly way to mean 'student-looking person,' similar to how Americans might say 'kiddo.' For 'colleague' use 同事 (tóngshì); for 'classmate at the same desk,' 同桌 (tóngzhuō).