Elegant style originally conceived here in ancient Rome (4)
I believe the answer is:
chic
'elegant style' is the definition.
(dressing fashionably)
'originally conceived here in ancient rome' is the wordplay.
'originally' suggests taking the first letters.
'here in ancient rome' becomes 'hic' ('here' in Latin).
The initial letter of 'conceived' is 'c'.
'c'+'hic'='CHIC'
(Other definitions for chic that I've seen before include "Modish" , "Fashionably elegant" , "Fashionable good taste" , "Stylish and elegant - in France" , "In vogue" .)