Brim, lip (3)
I believe the answer is:
rim
I believe this is a double definition.
'brim' is the first definition.
(I know that brim can be written as rim)
'lip' is the second definition.
(I know that lip can be written as rim)
(Other definitions for rim that I've seen before include "Edge or margin" , "An edge, canyon or cup" , "Edge, border" , "Curved edge" , "Brink" .)