Their Majesties the Emperor and Empress
Honorific term used in formal contexts to refer to the Emperor and Empress of Japan as a pair. Not used for foreign royalty.
Their Majesties the Emperor and Empress attended the ceremony.
I sincerely pray for the good health of Their Majesties the Emperor and Empress.
Refers only to the Empress, not the Emperor.
Compound of 両 (ryō, 'both') and 陛下 (heika, 'Your/His/Her Majesty').