Why is the word "Madrid" considered a toponym?

The term "Madrid" is classified as a toponym because it designates the name of a specific location. Toponyms are place names that provide information about geographic locations, which can include cities, countries, rivers, and other physical features. By identifying "Madrid" as a toponym, we see it indicates a distinct and recognizable area, specifically the capital city of Spain, which is significant in various contexts such as cultural, political, and economic realms.

The other options do not accurately define what a toponym is. For example, while a term used for all cities might include the concept of naming, it fails to capture the specificity that a toponym embodies. Similarly, indicating population size or referring to geographical features does not align with the definition of a toponym, as those aspects may relate to different categories of information about a locality rather than its name itself. Thus, the focus on "Madrid" as a specific location is what makes it a fitting example of a toponym.