Relate where American forward in torment (9)
I believe the answer is:
appertain
'relate' is the definition.
(I've seen this before)
'american forward in torment' is the wordplay.
'american' becomes 'a' (common abbreviation - e.g. in organisation names).
'forward' becomes 'pert' (I've seen this before).
'in' is an insertion indicator.
'torment' becomes 'pain'.
'pert' going inside 'pain' is 'ppertain'.
'a'+'ppertain'='APPERTAIN'
'where' is the link.
(Other definitions for appertain that I've seen before include "Be relevant to" , "Concern" , "Belong, relate (to)" , "Bear on" .)