This is what we found on Wikipedia regarding the Shamrock Tenors:

A country is a distinct area of land on Earth with a government that functions as a sovereign state, an unrecognized state, a constituent country, or a dependent territory. A country may consist of multiple nations, a structure known as a multinational state. Countries are often distinguished as developing countries or developed countries.

There is no universal agreement on the number of "countries" in the world. This ambiguity is a result of several countries not being recognized as sovereign states by the UN system, but are recognized by at least one UN member, known as "diplomatic recognition'. These countries often have disputed territories and have only partial recognition. A number of entities without recognition are also commonly considered a country.

Areas other than a political entity may be referred to as a "country," such as the West Country in England, "big sky country" (used in various contexts of the American West), "coal country" (used to describe coal-mining regions), cottage country or simply "the country" (used to describe a rural area). The term "country" is also used as a qualifier descriptively, such as country music or country living.

The definition and usage of the word "country" has fluctuated and changed over time. The Economist wrote in 2010 that "any attempt to find a clear definition of a country soon runs into a thicket of exceptions and anomalies."