Wow, there is only one meaning of "Byzantine"?
a. Of or relating to the ancient city of Byzantium.
b. Of or relating to the Byzantine Empire.
2. Of or belonging to the style of architecture developed from the fifth century ad in the Byzantine Empire, characterized especially by a central dome resting on a cube formed by four round arches and their pendentives and by the extensive use of surface decoration, especially veined marble panels, low relief carving, and colored glass mosaics.
3. Of the painting and decorative style developed in the Byzantine Empire, characterized by formality of design, frontal stylized presentation of figures, rich use of color, especially gold, and generally religious subject matter.
a. Of the Eastern Orthodox Church or the rites performed in it.
b. Of an Eastern Catholic church that maintains the worship of the Eastern Orthodox Church or the rites performed in it.
5. often byzantine
a. Of, relating to, or characterized by intrigue; scheming or devious: "a fine hand for Byzantine deals and cozy arrangements" (New York).
b. Highly complicated; intricate and involved: a bill to simplify the byzantine tax structure.