Part of semester, maybe (4)
I believe the answer is:
term
'part' is the definition.
(term is a kind of part)
'of semester maybe' is the wordplay.
'of' indicates a hidden word.
'TERM' can be found hidden inside 'semester maybe'.
(Other definitions for term that I've seen before include "Limited period of time" , "Part of the school year" , "An expression or period in office" , "Word; school session" , "Expression, or school period" .)