Longman Dictionary of Contemporary English
twin town
noun
EXAMPLES FROM CORPUS
▪ A choir is raising money to fund a trip to Reutlingen, twin town of Ellesmere Port and Neston.
▪ Tavernier, who is a native Lyon, Birmingham's twin town, has had a life long love affair with cinema.
▪ The initiative is part of Durham's appeal for food and medical aid for the county's twin town of Kostroma.
Wiktionary
twin town
n. A town paired with another through town twinning.
Wikipedia
Twin Town
Twin Town is a 1997 British crime film filmed and set in Swansea, Wales. It was directed by Kevin Allen and had a working title of Hot Dog; a hot dog van features in a number of scenes in the film. It stars real-life brothers Rhys Ifans (in his first major movie role) and Llŷr Ifans along with Dougray Scott. The director appears on screen, briefly seen as a show host on a TV set in the static caravan home of the twins while co-writer Paul Durden briefly appears as a rude taxi driver.