House party in Turkey, not essential (5)
I believe the answer is:
tudor
'house' is the definition.
(royal house)
'party in turkey not essential' is the wordplay.
'party' becomes 'do' (do is a kind of party).
'in' means one lot of letters goes inside another.
'not' suggests deleting specific letters.
'essential' becomes 'key' (I've seen this before).
'turkey' with 'key' taken away is 'tur'.
'do' put within 'tur' is 'TUDOR'.
(Other definitions for tudor that I've seen before include "Pre-Stuart royal house" , "Architectural style" , "Style of architecture in 15th c. England" , "Rose" , "Former English royal house" .)