the Two Ise Shrines
Refers collectively to the Inner Shrine (内宮, Naikū) and Outer Shrine (外宮, Gekū) of Ise Grand Shrine. Used in historical, religious, and cultural contexts.
Ise Grand Shrine consists of the two shrines, the Inner Shrine and the Outer Shrine.
外宮 is the other of the two shrines that together make up 二宮.
From 二 (ni, 'two') + 宮 (gū, 'shrine'). The reading にぐう is a standard on'yomi compound.