RS meaning in Country Names ?

Serbia ( (listen), SUR-bee-ə; Serbian Cyrillic: Србија, romanized: Srbija, pronounced [sř̩bija] (listen)), officially the Republic of Serbia (Serbian Cyrillic: Република Србија, romanized: Republika Srbija, pronounced [repǔblika sř̩bija] (listen)) is a country in Central and Southeast Europe. It is situated at the crossroads of the Pannonian Plain and the Balkans, bordering Hungary to the north, Romania to the northeast, Bulgaria to the southeast, North Macedonia to the south, Croatia and Bosnia and Herzegovina to the west, and Montenegro to the southwest; while claiming a border with Albania through the disputed territory of Kosovo. Serbia has a population of almost 7 million, with Belgrade as its capital and largest city.

Continuously inhabited since the Paleolithic Age, the territory of modern-day Serbia faced Slavic migrations in the 6th century, establishing several regional states in the early Middle Ages at times recognised as tributaries to the Byzantine, Frankish and Hungarian kingdoms. The Serbian Kingdom obtained recognition by the Holy See and Constantinople in 1217, reaching its territorial apex in 1346 as Serbian Empire. By the mid-16th century, the Ottomans annexed the entirety of modern-day Serbia; their rule was at times interrupted by the Habsburg Empire, which began expanding towards Central Serbia from the end of the 17th century while maintaining a foothold in Vojvodina. In the early 19th century, the Serbian Revolution established the nation-state as the region's first constitutional monarchy, which subsequently expanded its territory. Following casualties in World War I, and the subsequent unification of the former Habsburg crownland of Vojvodina with Serbia, the country co-founded Yugoslavia with other South Slavic nations, which would exist in various political formations until the Yugoslav Wars of the 1990s. During the breakup of Yugoslavia, Serbia formed a union with Montenegro, which was peacefully dissolved in 2006, restoring Serbia's independence as a sovereign state for the first time since 1918. In 2008, representatives of the Assembly of Kosovo unilaterally declared independence, with mixed responses from the international community while Serbia continues to claim it as part of its own sovereign territory.

Serbia is an upper-middle income economy, ranked 64th and "very high" in the Human Development Index domain. It is a unitary parliamentary constitutional republic, member of the UN, CoE, OSCE, PfP, BSEC, CEFTA, and is acceding to the WTO. Since 2014, the country has been negotiating its EU accession, with the aim of joining the European Union by 2025. Serbia has been formally adhering to the policy of military neutrality. The country provides universal health care and free primary and secondary education to its citizens.