Artificial language of emperor dismissing king (3)
I believe the answer is:
neo
'artificial language' is the definition.
(artificial language created by Arturo Alfandari)
'emperor dismissing king' is the wordplay.
'emperor' becomes 'nero' (Roman emperor).
'dismissing' is a deletion indicator.
'king' becomes 'r' (r is abbreviation for rex).
'nero' with 'r' taken out is 'NEO'.
'of' is the link.
(Other definitions for neo that I've seen before include "Prefix meaning new of modern form of" , "Prefix meaning new or recent" , "Hero of The Matrix films; new (prefix)" , "Prefix donating new" , "language" .)