Imperial Family
Imperial Household
noun
こうしつ
宮 (みや) Imperial Palace, Imperial Family
皇室 (こうしつ) Imperial Family, Imperial Household
殿堂 (でんどう) Palace, Sanctuary, Hall Of Fame
Yuri and Jisho say 皇室 means Imperial Household.
Koichi こう shits しつ in the Imperial Palace.