free period
US /ˈfriː ˌpɪr.i.əd/
UK /ˈfriː ˌpɪr.i.əd/

1.
período libre, hora libre
a period during the school day when a student does not have a class and is free to do other things
:
•
During my free period, I usually go to the library to study.
Durante mi período libre, normalmente voy a la biblioteca a estudiar.
•
Do you have a free period next?
¿Tienes un período libre después?