'Royal house' in the Bible

Also Vashti the queen made a feast for the women in the royal house which belonged to king Ahasuerus.

So then Esther was taken unto King Ahasuerus, into his royal house, in the tenth month, the same, was the month Tebeth, - in the seventh year of his reign.

And it cometh to pass on the third day, that Esther putteth on royalty, and standeth in the inner-court of the house of the king over-against the house of the king, and the king is sitting on his royal throne, in the royal-house, over-against the opening of the house,

“And concerning the royal house of the king of Judah [you shall say], ‘Hear the word of the Lord,

Hear this, priests!Pay attention, house of Israel!Listen, royal house!For the judgment applies to youbecause you have been a snare at Mizpahand a net spread out on Tabor.

and at Beth-El do not add to prophesy any more, for it is the king's sanctuary, and it is the royal house.'