Question

SPANISH: how do you say next semester? like, i have a class next semester

Answer 1

`Semester - semestre`

`Tengo una clase proximo semestre`

Answer 2

"Next" = "Próximo"
"Semester" = "Semestre"

It's important to include the accent (so "proximo" is incorrect), and "semestre" is a masculine noun so you must include "el" before it if necessary. So with that, here are the optional ways you can say you have a class next semester:

"Yo tengo una clase en el próximo semestre."
"Yo tengo una clase el próximo semestre."
"Tengo una clase en el próximo semestre."
"Tengo una clase el próximo semestre."

Inserting "yo" and "en" are completely optional, the sentence is fine without them but you can put them in if you'd like to be more specific.