Romanian word subteran comes from Latin terra, and later Latin subterraneus (Underground, subterranean.)

Detailed word origin of subteran

Dictionary entry	Language	Definition
terra	Latin (lat)	the world, the globe, earth as a celestial object. Earth's surface (dry land and sea together; as opposed to the heavens). A land, a region, a country. Earth, soil, dirt. Ground, dry land.
subterraneus	Latin (lat)	Underground, subterranean.
subteran	Romanian (ron)	Underground, subterranean.

Words with the same origin as subteran