noun
woman with the title "in"; imperial lady granted the "in" title
Historical honorific title given to an empress, imperial princess, or high-ranking consort, often after taking Buddhist vows or upon retirement. The title is part of the 院 (in) system; see cross-reference to 院 sense 6.
See also: 院
建礼門院は平清盛の娘で、高倉天皇の中宮として女院となった。
Kenreimon-in was a daughter of Taira no Kiyomori and became a nyoin as the empress of Emperor Takakura.
女院の称号
The title of nyoin was granted frequently from the Insei period through the Kamakura period.
院 (sense 6) refers to the title 'in' itself, often given to retired emperors or high-ranking nobles. 女院 specifically denotes a woman who has received this title.
上皇 is a retired emperor, while 女院 is a woman (empress, princess, etc.) granted the 'in' title, often with similar prestige but distinct in gender and specific historical usage.
Compound of 女 (woman) and 院 (the 'in' title). The term emerged in the Heian period as part of the 院 system, where retired emperors and certain high-ranking women were granted the honorific title 'in'.