thirdperiod

noun
UK /ˌθɜːd ˈpɪəriəd/
US /ˌθɝːd ˈpɪriəd/

The third period is the class you go to after the second one in school.

We have math in third period today.


OTHER MEANINGS

2. The third section of a sports game, such as hockey.

Our team scored two goals in the third period.

3. The third stretch of time in a school day or work shift.

The bell for third period rings at ten o'clock.

4. The third repeated part of a pattern or cycle.

The third period of the experiment showed the best results.