Book parts in plays (4)
I believe the answer is:
acts
I believe this is a triple definition!
'book' is the first definition.
(book of the Bible)
'parts' is the second definition.
(I have seen 'Parts of play ' mean 'acts' so perhaps 'parts' could also mean 'acts')
'in' is a link.
'plays' is the third definition.
('act' can be a synonym of 'play')
(Other definitions for acts that I've seen before include "Done deeds" , "Fifth NT book" , "these for variety show" , "spiritual work" , "Laws passed" .)