Part, division (7)
I believe the answer is:
section
I believe this is a double definition.
'part' is the first definition.
(I know that section is a kind of part)
'division' is the second definition.
(I know that section is a type of division)
(Other definitions for section that I've seen before include "surgical procedure" , "Division, portion" , "Distinct part" , "Department, division" , "Divide; part" .)