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

A country is an area of land, which has its own government and laws, or used to have them, such as a state, a nation, a nation state, or other political entity. When referring to a specific polity, the term "country" may refer to a sovereign state, a state with limited recognition, a constituent country, or a dependent territory. Most sovereign states, but not all countries, are members of the United Nations.

There is no universal agreement on the number of "countries" in the world with a range between 193 to 237. This ambiguity is a result of several states having disputed sovereignty status or limited recognition, and a number of non-sovereign entities are commonly considered countries. 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."

Areas much smaller 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), 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.