your honor; his/her honor
Honorific title used to address or refer to a high-ranking official, such as a minister or ambassador. Often used as a suffix attached to a name or title.
大臣台下は式典に出席された。
His Honor the Minister attended the ceremony.
It is an honor to meet Your Excellency the Ambassador.
Compound of 台 (dai, 'platform' or 'high seat') and 下 (ka, 'below'), originally referring to the area below a high seat where a superior sits, and by extension a respectful way to refer to the person themselves.