Cast a spell on portal (8)
I believe the answer is:
entrance
I believe this is a double definition.
'cast a spell on' is the first definition.
(I've seen this before)
'portal' is the second definition.
(I know that portal can be written as entrance)
(Other definitions for entrance that I've seen before include "Send" , "Means or place of going in" , "Way in - bewitch" , "Vestibule" , "Ingress" .)