joint issue
the release of stamps or postal stationery by two or more countries to commemorate the same topic, event or person
en-US/ˈd͡ʒɔɪnt ˈɪʃu/
en-GB/ˈd͡ʒɔɪnt ɪsuː/
the release of stamps or postal stationery by two or more countries to commemorate the same topic, event or person