Specifications for limited periods (5)
I believe the answer is:
terms
'periods' is the definition.
(term is a kind of period)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for terms that I've seen before include "Opportunities to study" , "Conditions (contract)" , "Work periods" , "Times" , "Stipulated requirements" .)