Meaning of UNDERGROUND in English

UNDERGROUND

The adverb is pronounced /ʌndə(r)graʊnd/. The noun and adjective are pronounced /ʌndə(r)graʊnd/.

Frequency: The word is one of the 3000 most common words in English.

1.

Something that is underground is below the surface of the ground.

Solid low-level waste will be disposed of deep underground...

The plane hit so hard that one engine was buried 16 feet underground.

ADV : ADV after v

Underground is also an adjective.

...a run-down shopping area with an underground car park.

...underground water pipes.

ADJ : ADJ n

2.

The underground in a city is the railway system in which electric trains travel below the ground in tunnels. ( BRIT; in AM, use subway )

...a woman alone in the underground waiting for a train...

He crossed London by underground...

N-SING : the N , also by N

3.

In a country which is controlled by an enemy or has a harsh government, the underground is an organized group of people who are involved in illegal activities against the people in power.

These US dollars were smuggled into the country during the war, to aid the underground.

N-SING : the N

4.

Underground groups and activities are secret because their purpose is to oppose the government and they are illegal.

They are accused of organising and financing an underground youth movement.

ADJ : ADJ n

5.

If you go underground , you hide from the authorities or the police because your political ideas or activities are illegal.

After the violent clashes of 1981 they either went underground or left the country.

ADV : ADV after v

Collins COBUILD Advanced Learner's English Dictionary.      Английский словарь Коллинз COBUILD для изучающих язык на продвинутом уровне.