0
Crown is provided so that the belt should remain in the centre of pully rim. In the absence of crown the belt will slip sideways. - Deepak
A pork pie hat has a circular brim with a flat top. The top of the hat, while flat, has a distinctive crown shape.
A flat head screwdriver.
A boater is a person who travels by boat, or a stiff straw hat with a flat brim and crown.
Yes or it can be the same as the wall paint if it should be flat.