End of school period (4)
I believe the answer is:
term
I believe this is a double definition.
'end' is the first definition.
(I've seen this before)
'school period' is the second definition.
(I've seen this before)
'of' acts as a link.
(Other definitions for term that I've seen before include "Limited period of time" , "Contract condition; school time" , "Spell - word" , "Expression, or school period" , "Word or expression for some particular thing" .)