Early 17th century: from Latin subterraneus (from sub- 'below' + terra 'earth') + -an.

• terrace from early 16th century:

  In the early 16th century a terrace was an open gallery, and later it came to mean a platform or balcony in a theatre. A terrace of houses was originally a row built slightly above the level of the road—the first terrace of houses was mentioned in the 1760s, at first in street names like Adelphi Terrace. The source was a medieval French word meaning ‘rubble, platform’, based on Latin terra ‘earth’, the source of many other English words such as terrain (early 18th century), terrestrial (Late Middle English), territory (Late Middle English), and subterranean (early 17th century). A territory was originally the area surrounding a town and was subject to its laws. To say that something goes with the territory is to say that it is an unavoidable result of a situation. Territory here is probably used in the sense ‘the area in which a sales representative or distributor has the right to operate’, which developed in the US in the early 20th century. In Arthur Miller's play Death of a Salesman (1949), the central character Willy Loman tells his son that a salesman has to dream: ‘It comes with the territory.’ See also kop