Vent; shop (6)
I believe the answer is:
outlet
I believe this is a double definition.
'vent' is the first definition.
(I know that vent can be written as outlet)
'shop' is the second definition.
(outlet can mean a shop or market)
(Other definitions for outlet that I've seen before include "Maths relationship" , "Vent, means of escape" , "Way of release" , "Exit pipe" , "Store" .)