Dome where king is regularly seen on throne (5)
I believe the answer is:
igloo
'dome' is the definition.
(thesaurus)
'king is regularly seen on throne' is the wordplay.
'is regularly seen' indicates alternate letters.
'on' is a charade indicator (letters next to each other).
'throne' becomes 'loo' (both can mean a toilet).
The alternate letters of 'king' are 'ig'.
'ig'+'loo'='IGLOO'
'where' is the link.
(Other definitions for igloo that I've seen before include "Snow-house" , "Inuit ice house" , "northern home" , "Inuit ice home" , "Eskimo's home" .)