1 (also Balkan Mountains) a range of mountains stretching eastwards across Bulgaria from the Serbian frontier to the Black Sea. The highest peak is Botev Peak (2,375 m; 7,793 ft).
2the countries occupying the part of SE Europe lying south of the Danube and Sava Rivers, forming a peninsula bounded by the Adriatic and Ionian Seas in the west, the Aegean and Black Seas in the east, and the Mediterranean in the south.
Balkans in other Oxford dictionaries
Definition of Balkans in the US English dictionary