Her Majesty's cash? (5)
I believe the answer is:
crown
This clue could be a double definition.
'her majesty's' is the first definition.
(thesaurus)
'cash?' is the second definition.
The definition and answer can be both related to property as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
Can you help me to learn more?
(Other definitions for crown that I've seen before include "The sovereign" , "Old coin; whack on head" , "Headdress, coin" , "Royal headdress" , "Old five shilling piece" .)