Limitrophe states

Limitrophe states are territories situated on a border or frontier. In a broad sense, it means border countries—any group of neighbors of a given nation which border each other thus forming a rim around that country. The English term derives from "pays limitrophes", a term in diplomatic French.

In ancient Rome, the term referred to provinces at the borders of the Roman Empire (Latin: limitrophus), which were obliged to provide billeting of the limitanei legions deployed on their territory, mostly in limes.

In modern history, it was used to reference provinces which seceded from the Russian empire at the end of World War I, during the Russian Civil War (1917–1922), thus forming a kind of belt separating the Soviet Russia from the Western powers.

Before the Treaty of Versailles was signed on 28 June 1919 and even after it was not clear yet, which territories of the Russian Empire, either occupied by German troops or engaged in the Civil War in Russia, may maintain their independence, which they started to proclaim from late 1917. Thus the very composition of the Limitrophe zone was uncertain and varied widely. Arguing that these nations were then "the cards to change hands in big political games", among them the Baltic peoples, Poles, Lithuanians, Ukrainians, Belarusians, and so on.

The usage of term "limitrophe states" continued after World War I. Treaties were signed through the beginning of World War II. The Small Soviet Encyclopedia (1929) defines the limitrophe states as "states formed from the outskirts of the former Tsarist Russia, mainly from the western provinces". It includes in their list Estonia, Latvia, and Lithuania, adding "and, partially, Poland and Finland". Nine years later the Ushakov's Explanatory Dictionary (1938) also syntactically 'separates' Finland from the three Baltic States: ("Estonia, Lithuania, Latvia and Finland as well"). However, Poland is not mentioned in this list.

...
Wikipedia