A buffer state is a country geographically lying between two rival or potentially hostile great powers.
By contrast, these concerns do not apply to nonbuffer states, where powers face no competition for influence or control.
The concept of buffer states is part of a theory of the balance of power that entered European strategic and diplomatic thinking in the 18th century.
After the First World War, notable examples of buffer states were Poland and Czechoslovakia, situated between major powers such as Germany and the Soviet Union.
Lebanon is another significant example, positioned between Syria and Israel, thereby experiencing challenges as a result.