subterranean
Word family nounsubterraneadjectivesubterraneoussubterrenesubterraneansubterrestrialadverbsubterraneously
sub·ter·ra·ne·an /ˌsʌbtəˈreɪniən◂/ adjectiveadj [usually before noun] HEUNDER/BELOWbeneath the surface of the Earth 地下的,地表下的 SYN underground subterranean passage 地下通道
Origin subterranean (1600-1700) Latin subterraneus, from terra “earth”