Formal or literary term for a palace or the imperial household. In modern Japanese, 宮殿 (きゅうでん) is more common for 'palace', and 皇室 (こうしつ) for 'imperial family'.
古い文献には、宮室の造営についての記述がある。
Old documents contain descriptions of the construction of palaces.
宮室の儀式は厳かに執り行われた。
The imperial family's ceremony was solemnly conducted.
Compound of 宮 (palace, shrine) and 室 (room, chamber). The exact historical derivation is uncertain; the word is used in classical Chinese and was adopted into Japanese with similar meanings.