adjective / adverb / noun
underground
Located below the ground's surface.
The underground garage keeps our car out of the rain.
Etymology
The compound directly identifies a position beneath the ground. The spatial relation supplies the literal meaning without a figurative intermediate sense.
More examples
- The water pipes run underground beneath the street.
- Moles dig underground tunnels in search of food.
- Some tree roots extend deep underground.
Forms
underground
Similar words
- subterranean
- More formal; often describes caves, passages, or other underground spaces.
- subsurface
- Often technical; means beneath a surface, not necessarily the ground.