Company or business partnership (4)
I believe the answer is:
firm
I believe this is a double definition.
'company' is the first definition.
(firm can mean a company or business)
'business partnership' is the second definition.
(I've seen this before)
(Other definitions for firm that I've seen before include "Hard" , "Resolute; company" , "Solid; secure" , "decided" , "Strong - business" .)