link (a town or district) with another in a different country or cause (two towns or districts) to be linked, for the purposes of friendship and cultural exchange

the Russian city of Kostroma is twinned with Durham

one of two children or animals born at the same birth

experiments were carried out using sets of identical twins

the twins were approaching their third birthday

I thought you must have a double or be a twin

something containing or consisting of two matching or corresponding parts