The term Matryoshka-nationalism comes from the name of a wooden Russian doll called matryoshka which, reveals another, smaller doll inside, with the latter containing an even smaller doll. 

The notion of Matryoshka-nationalism as a specific phenomenon of post-Soviet nationalism refers to separatist movements that emerged upon the dissolution of the USSR and implies the existence of a smaller ethnic group within a larger one. It became a trend in some countries in the early 1990s, when the political elites of the ethnic groups and entities that had previously enjoyed quasi-autonomy started demanding either full sovereignty and independence from their parent states or aspired to be part of a different state. 

The most notable example happened in Azerbaijan that obtained independence in the aftermath of the Soviet Union`s collapse; an ethnic minority started a secessionist movement in Nagorno-Karabakh. The similar situation occurred in Transnistrian region of Moldova, Abkhazia and South Ossetia regions of Georgia, Crimea and Donbas of Ukraine. These conflicts still remain unresolved and, in the case of Nagorno-Karabakh, still take a significant human toll. 

Secessionist attempts also occurred within the post-Yugoslavian states in the 1990s. The Republic of Serbian Krajina attempted to secede from the newly independent Croatia, the Republika Srpska from Bosnia & Herzogovina in the 1990s. But both self-proclaimed secessionist republics were later re-incorporated into their respective parent states.