noun
imperial prince; prince of royal blood
A title for a male member of the Japanese imperial family who is a son or grandson of an emperor. Not used for princes of foreign royalty.
親王殿下が式典にご出席になった。
His Imperial Highness the Prince attended the ceremony.
秋篠宮親王は天皇陛下の弟
Prince Akishino is the younger brother of His Majesty the Emperor.
From Middle Chinese 親王 (tshin hjwang), meaning 'prince of the blood'. The reading しんのう is the go-on reading of the characters.