also: もとみや
noun
Refers to the principal shrine building within a shrine complex, as opposed to branch shrines (末社). Also used in proper names of specific shrines.
See also: 本社
この神社の本宮は山の上にある。
The main shrine of this shrine is on top of the mountain.
熊野本宮大社
Kumano Hongū Taisha is in Wakayama Prefecture.
Compound of 本 (hon, 'main') and 宮 (gū, 'shrine'). The reading もとみや uses the native Japanese reading of the characters.