Weird dialect used in stronghold (7)
I believe the answer is:
citadel
'stronghold' is the definition.
(I know that citadel is a type of stronghold)
'weird dialect' is the wordplay.
'weird' is an anagram indicator.
'dialect' with letters rearranged gives 'CITADEL'.
'used in' acts as a link.
(Other definitions for citadel that I've seen before include "Fortress overlooking a city" , "where Salvationists meet" , "Urban fortress" , "place of refuge" , "Urban stronghold - dialect (anag)" .)