Un"der*ground` (?), n. The place or space beneath the surface of the ground; subterranean space.

A spirit raised from depth of underground.

Un"der*ground`, a. 1. Being below the surface of the ground; as, an underground story or apartment.

2. Done or occurring out of sight; secret. [Colloq.]

Un"der*ground`, adv. Beneath the surface of the earth.

Un"der*ground` (?), n. The place or space beneath the surface of the ground; subterranean space.

A spirit raised from depth of underground.

Un"der*ground`, a. 1. Being below the surface of the ground; as, an underground story or apartment.

2. Done or occurring out of sight; secret. [Colloq.]

Un"der*ground`, adv. Beneath the surface of the earth.

• (no (compar) or (superl)) Below the ground; below the surface of the Earth.
       There is an underground tunnel that takes you across the river.
  
• Hidden, furtive, secretive.
       These criminals operate through an underground network.
  
• Of music, art, etc, outside the mainstream.
  
• Below the ground.
       The tunnel goes underground at this point.
  
• Secretly.
  
• An underground railway.
  
• (with the) A movement or organisation of people who resist political convention.
  
• (with the) A movement or organisation of people who resist artistic convention.
  
  French
• underground (outside the mainstream)
  
• the underground (people who resist artistic convention)
  
  Italian
• the underground (people who resist artistic convention)