Subterránea
Subterránea is the feminine form of the Spanish adjective subterráneo, meaning underground or subterranean. The term comes from Latin subterraneus, formed from sub- “under” and terra “earth.” It is used to describe things that are located, occurring, or operating beneath the surface of the ground.
The word appears in a variety of contexts. In geography and geology, it describes features such as
Grammatically, subterránea functions as the feminine form of the adjective; the corresponding masculine form is subterráneo.