proper noun/y.njɔ̃ de ʁe.py.blik sɔ.sja.list sɔ.vje.tik/
Union des républiques socialistes soviétiques is feminine in French.
Union of Soviet Socialist Republics (a former transcontinental country in Europe and Asia (1922–1991), now split into Russia and 14 other countries; short form Union soviétique; abbreviation URSS)