noun
sister city; twin town
A city that has a formal partnership with another city, often for cultural or economic exchange.
京都市とパリ市は姉妹都市です。
Kyoto City and Paris are sister cities.
姉妹都市提携を結ぶ。
To form a sister city relationship.
Compound of 姉妹 (shimai, 'sisters') and 都市 (toshi, 'city'), literally 'sister city'.