Underground; = subterranean, adj. 1.

Subterranean, underground.

= under-earth, adj.

Of an inanimate object: existing, lying, or situated below the surface of the earth; formed or constructed underground, either naturally or by…

Existing or situated underground; = subterranean, adj. 1b. Also occasionally as adv.: †below the ground (obsolete).

Underground; = subterranean, adj. 1.

Found below the surface of the ground.

= subterranean, adj. 1.

= subterranean, adj.

Existing or occurring underground or in the underworld; subterranean.

Subterranean.

= subterranean, adj.

Underground; = subterranean, adj. 1.

In the middle of the earth; subterranean.

= hypogean, adj., subterranean.

Of or relating to hell or the underworld; infernal. Also: underground, subterranean. Cf. supermundane, adj.

Existing, lying, or operating under the surface of esp. the earth or a body of water; (also) of or relating to the subsurface. Also figurative.

Underground; = hypogean, adj.

Existing or growing beneath the surface of the ground; underground.

Situated or constructed below ground level; underground.

Subterranean.