Door half-centred initially in Corinthian order of architecture (5)
I believe the answer is:
doric
'order of architecture' is the definition.
(I've seen this in another clue)
'door half-centred initially in corinthian' is the wordplay.
'half' means to take half the letters.
'centred initially in corinthian' becomes 'ric' (I can't justify this - if you can you should believe this answer much more).
'door' halved is 'do'.
'do'+'ric'='DORIC'
Can you help me to learn more?
(Other definitions for doric that I've seen before include "Classical building style" , "One classical order in architecture" , "hairdo tips costly, for the most part" , "Relating to a classical order of architecture" , "Type of classical architecture" .)