Imperial Household (Japan)
The Imperial Household (内廷皇族 Naitei kōzoku, also known as the Inner court), is the term for the Emperor of Japan's direct family and includes the Empress, the Empress dowager, the Grand Empress Dowager, the Imperial Crown Prince, (皇太子, kōtaishi, the heir to the throne who is son of the current Emperor), and the Imperial Crown Princess (皇太子妃, kōtaishihi, the wife of the Imperial Crown Prince), and any unmarried children of the above.
Currently Prince Fumihito holds the title of kōshi (皇嗣) as he is not the son of the current emperor, thus is not part of the Imperial household. His wife, Princess Kiko, currently holds the title kōshihi (皇嗣妃), as she is the wife of the crown prince, and not the wife of the Imperial Crown Prince. Princess Abe is the only woman to have held the title Imperial Crown Prince in her own right.
The Empress Emerita, based on the Emperor Abdication Law, is considered an equivalent to Empress Dowager (a title she will receive should her husband predecease her). The Emperor and Emperor Emeritus are usually excluded from this.