A more thorough explanation:

SUBJACENT

subjacent (səb-jay-sənt), adj. Located underneath or below.

Example: The basement is subjacent to the main floor of the house.

Another example: The roots of a tree are subjacent to the soil.

The term subjacent refers to something that is located beneath or below something else. In the first example, the basement is located underneath the main floor of the house. In the second example, the roots of a tree are located below the soil. These examples illustrate the definition of subjacent by showing how something can be situated underneath or below another object or surface.