A more thorough explanation:

CONTIGUITY

Contiguity is the state or condition of being next to or touching something else.

For example, if two pieces of land share a common border, they are said to have contiguity.

The term contiguity refers to the physical proximity of two or more objects or entities. It is often used in geography to describe the relationship between neighboring regions or countries. For instance, the United States and Canada share a long border, which is an example of contiguity. Similarly, two adjacent buildings or rooms can be said to have contiguity because they are next to each other.