sister museum; sister building; sister pavilion
Refers to a building that is part of a sister-institution relationship, typically a museum, gallery, or cultural pavilion. Often used in the context of cultural exchange or institutional partnerships.
The sister museum of this art museum is in Paris.
An exchange exhibition with the sister museum was held.
姉妹校 is a sister school, used for educational institutions, whereas 姉妹館 is for buildings like museums or pavilions.
Compound of 姉妹 (shimai, 'sisters') and 館 (kan, 'building, hall'). The term follows the pattern of other 'sister' institutional compounds like 姉妹都市 (sister city).