D defs.my
Entry 1 sense Webster, 1913

Subterranean

/səb-tẽr-ān'-ē-ən/ · Sub·ter·ra·ne·an · IPA /ˌsʌbtəˈɹeɪniən/
01 a. Being or lying under the surface of the earth; situated within the earth, or under ground; as, subterranean springs; a subterraneous passage.
  1. 1.
    Being or lying under the surface of the earth; situated within the earth, or under ground; as, subterranean springs; a subterraneous passage.