UNDERGROUND

Pronunciation (US):

(GB):

IPA (US):

 Dictionary entry overview: What does underground mean? 

• UNDERGROUND (noun)
  The noun UNDERGROUND has 2 senses:

1. a secret group organized to overthrow a government or occupation force

2. an electric railway operating below the surface of the ground (usually in a city)

  Familiarity information: UNDERGROUND used as a noun is rare.

• UNDERGROUND (adjective)
  The adjective UNDERGROUND has 2 senses:

1. under the level of the ground

2. conducted with or marked by hidden aims or methods

  Familiarity information: UNDERGROUND used as an adjective is rare.

• UNDERGROUND (adverb)
  The adverb UNDERGROUND has 2 senses:

1. in or into hiding or secret operation

2. beneath the surface of the earth

  Familiarity information: UNDERGROUND used as an adverb is rare.

 Dictionary entry details 

• UNDERGROUND (noun)

Sense 1

Meaning:

A secret group organized to overthrow a government or occupation force

Classified under:

Nouns denoting groupings of people or objects

Synonyms:

resistance; underground

Hypernyms ("underground" is a kind of...):

revolutionary group (a political unit organized to promote revolution)

Hyponyms (each of the following is a kind of "underground"):

Maquis (the French underground that fought against the German occupation in World War II)

Derivation:

underground (conducted with or marked by hidden aims or methods)

Sense 2

Meaning:

An electric railway operating below the surface of the ground (usually in a city)

Classified under:

Nouns denoting man-made objects

Synonyms:

metro; subway; subway system; tube; underground

Context example:

in Paris the subway system is called the 'metro' and in London it is called the 'tube' or the 'underground'

Hypernyms ("underground" is a kind of...):

railroad; railroad line; railway; railway line; railway system (line that is the commercial organization responsible for operating a system of transportation for trains that pull passengers or freight)

• UNDERGROUND (adjective)

Sense 1

Meaning:

Under the level of the ground

Synonyms:

belowground; underground

Context example:

underground caverns

Similar:

subsurface (beneath the surface)

Sense 2

Meaning:

Conducted with or marked by hidden aims or methods

Synonyms:

clandestine; cloak-and-dagger; hole-and-corner; hugger-mugger; hush-hush; secret; surreptitious; undercover; underground

Context example:

underground resistance

Similar:

covert (secret or hidden; not openly practiced or engaged in or shown or avowed)

Derivation:

underground (a secret group organized to overthrow a government or occupation force)

• UNDERGROUND (adverb)

Sense 1

Meaning:

In or into hiding or secret operation

Context example:

the organization was driven underground

Sense 2

Meaning:

Beneath the surface of the earth

Context example:

water flowing underground

 Context examples 

The underground stems are used in some cultures to treat certain stomach problems.

(Curcuma longa, NCI Dictionary)

Their analysis suggests it is possible for liquid water to reach from the moon’s underground sea all the way to its surface.

(101 Geysers on Icy Saturn Moon, NASA)

A 2016 report also cast doubt on possible sources of underground water at RSL sites.

(Recurring Martian Streaks: Flowing Sand, Not Water?, NASA)

The little man took him by the hand, and led him through an underground passage, but he did not forget to take the blue light with him.

(Fairy Tales, by The Brothers Grimm)

Called mycorrhizal fungi, these organisms spread underground for miles, scavenging for nutrients that they trade with trees for sugars the trees make during photosynthesis.

(NASA Satellite Images Uncover Underground Forest Fungi, NASA)

"Plants get more water-efficient and leak less underground soil moisture through their pores in a carbon-rich atmosphere," said study co-author Mike Pritchard of UCI.

(Plant physiology will be major contributor to future river flooding, National Science Foundation)

A short, underground bud-like stem covered by enlarged and fleshy scales containing stored food.

(Bulb, Food and Drug Administration)

At 246 miles (396 kilometers) wide, Mimas is too small to have retained internal heat from its formation, so some other source of energy would be required to maintain an underground ocean.

(Saturn Moon May Hide a 'Fossil' Core or an Ocean, NASA)

Dragon's Breath Cave, the largest non-subglacial underground lake on Earth, is buried there.

(Sleeping sands of the Kalahari awaken after more than 10,000 years, NSF)

Martian water ice is locked away underground throughout the planet's mid-latitudes.

(NASA's Treasure Map for Water Ice on Mars, NASA)