Bible Dictionaries
Underground

Webster's Dictionary

(1):

(a.) Done or occurring out of sight; secret.

(2):

(n.) The place or space beneath the surface of the ground; subterranean space.

(3):

(adv.) Beneath the surface of the earth.

(4):

(a.) Being below the surface of the ground; as, an underground story or apartment.

Bibliography Information
Webster, Noah. Entry for 'Underground'. Noah Webster's American Dictionary. https://www.studylight.org/​dictionaries/​eng/​web/​u/underground.html. 1828.