Your Majesty; His Majesty; Her Majesty
Honorific title used for the current emperor or a reigning monarch. Can be used as a standalone noun or as a suffix attached to the monarch's name or title.
His Majesty attended the ceremony.
It is an honor to meet His Majesty the Emperor.
The ambassador had the opportunity to have an audience with His Majesty.
The people gave His Majesty a grand welcome.
His Majesty visited the disaster-stricken area.
陛下 is the honorific title used when addressing or referring to the emperor directly, while 帝 is a plain noun naming the emperor himself.
陛下 addresses the reigning emperor or monarch, while 殿下 is used for princes, princesses, and other non-reigning royals.
陛下 is reserved for a reigning monarch, whereas 閣下 is an honorific used for high government officials, generals, or ambassadors.
陛下 is reserved for the Emperor and Empress, while 妃殿下 is used for princesses; both end in the honorific suffix 下 but mark different ranks within the imperial family.
Standard kanji spelling for addressing or referring to an emperor, empress, king, or queen.
From Chinese 陛下 (bìxià), originally meaning 'below the steps' (of the throne), used as an indirect respectful address for the emperor.