- Drainage basin (Wikipedia)
A drainage basin is an area of land where all flowing surface water converges to a single point, such as a river mouth, or flows into another body of water, such as a lake or ocean. A basin is separated from adjacent basins by a perimeter, the drainage divide, made up of a succession of elevated features, such as ridges and hills. A basin may consist of smaller basins that merge at river confluences, forming a hierarchical pattern.
- Country (Wikipedia)
A country is a distinct part of the world, such as a state, nation, or other political entity. When referring to a specific polity, the term “country” may refer to a sovereign state, states with limited recognition, 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 since several states have disputed sovereignty status, limited recognition and a number of non-sovereign entities are commonly called countries.