What type of region has clearly defined boundaries?

A formal region is characterized by clear, defined boundaries that are typically based on measurable criteria such as political, physical, or cultural attributes. For example, countries, states, or specific areas defined by language or religion fall into this category, as they possess distinct borders recognized by legal or official documentation.

In contrast, functional regions are organized around a central hub or node and may not have fixed boundaries, as their influence can extend outward based on connectivity or interaction. Vernacular regions, or perceptual regions, are based on people's perceptions or cultural identities, lacking precise borders, leading to subjective interpretations of where one region ends and another begins.