'''Kakaisaran Bizantium''' utawa '''Kakaisaran Romawi Timur''' (ejaan liya: '''Bizantin''', '''Byzantin''', '''Byzantine''') iku wilayah wétan [[Kakaisaran Romawi]] sing wicara nganggo [[basa Yunani|abasa Yunani]]<ref>{{harvnb|Millar|2006|pages=2, 15}}; {{harvnb|James|2010|p=5}}: "But from the start, there were two major differences between the Roman and Byzantine empires: Byzantium was for much of its life a Greek speaking empire oriented towards Greek, not Latin culture; and it was a Christian empire."</ref> ing [[Abad Kuna]] lan [[Abad Tengahan|Tengahan]]. Pedunung lan tangga-teparo Kakaisaran Bizantium njuluki negri iki Kakaisaran Romawi utawa Romania ([[Basa Yunani|Yunani]]: {{Polytonic|Ῥωμανία}}, ''Rhōmanía'').
