What does "underground" mean?
Regions beneath the surface of the earth, both natural (eg. caves) and man-made (eg. mines).
Underground
/ˌʌndəˈɡɹaʊnd/ adj, adv, name, noun, verb
adj, adv, name, noun, verb ·Very common ·High school level
Meaning at a glance
- Primary sense: Regions beneath the surface of the earth, both natural (eg. caves) and man-made (eg. mines).
- Grammar: underground is listed as adj, adv, name, noun, verb.
- Nearest alternatives: metro, resistance, subway, subway system.
- Useful contrasts: aboveground flower, geographic surface, mainstream pop.
- Usage evidence: London is such a large city that visitors must use buses and the underground railway to get about.
How to use "underground"
- Start with the primary definition, then check the part of speech before placing the word in a sentence.
- Compare nearby synonyms to make sure "underground" carries the exact meaning, tone, and strength you need.
- Use the example sentence as a context check. If your sentence uses the word differently, confirm that the grammar still fits.
Meaning check
- Does the word fit the sentence's grammar?
- Does it match the intended tone rather than only the dictionary definition?
- Would a simpler synonym be clearer for the reader?
- Is there enough surrounding context to prevent ambiguity?
Source and review context
This entry combines structured lexical data with WordToolSet review checks. Definitions, examples, synonyms, and usage notes may come from different source tables, so the page is designed to show evidence from more than one angle before you rely on "underground" in a final draft.
If a word has several senses, prefer the sense that matches your sentence's grammar and surrounding context. A correct definition can still be the wrong choice when the sentence needs a different register, emphasis, or level of specificity.
Before you rely on this definition
Read the first definition as a starting point, then check the example, synonyms, and part of speech before treating "underground" as the right word for your sentence.
If your draft is formal, technical, persuasive, or sensitive, compare "underground" with a nearby alternative so the final choice matches both meaning and reader expectation.
Compare nearby meanings
- Use synonyms when you need a softer, stronger, simpler, or more specific word.
- Use antonyms to check the boundary of the meaning and avoid accidental contrast.
- Use the example sentence to confirm the word behaves naturally in context.
- Keep the original wording when a replacement adds complexity without improving precision.
Definition decision workflow
1. Identify the role
Check whether "underground" is acting as adj, adv, name, noun, verb in your sentence. A definition is only useful when the grammar matches the way the word is being used.
2. Test the nearest option
Compare it with "metro" and other nearby choices to see whether the sentence needs a softer, stronger, or more familiar word.
3. Confirm with context
Use the example sentence below as an evidence check, then read your own sentence out loud to catch tone or rhythm problems.
Review note: Definition pages are checked for source coverage, sentence evidence, synonym support, and editorial insight before they are treated as approval-ready pages. If the evidence is too thin, the page remains available to users but is kept out of the approval-facing indexed inventory.
Final meaning check
Before publishing a sentence with "underground", ask whether the word helps the reader understand the idea faster. A precise word should reduce confusion, not simply make the sentence look more polished.
When the definition, synonym evidence, and example context point in the same direction, the word is usually a safer choice. When they conflict, revise the sentence or choose a clearer alternative.
Definitions
Noun
- 1 Regions beneath the surface of the earth, both natural (eg. caves) and man-made (eg. mines).
- 2 an electric railway operating below the surface of the ground (usually in a city) wordnet
- 3 Synonym of subway: a railway that is under the ground. British
"London Underground"
- 4 a secret group organized to overthrow a government or occupation force wordnet
- 5 A movement or organisation of people who resist political convention. with-definite-article
"the French underground during World War II"
Show 1 more definition
- 6 A movement or organisation of people who resist artistic convention. with-definite-article
Verb
- 1 To route electricity distribution cables underground.
"One is to underground where no other alternative will work, and this method should be used universally in urban regions as it now is in “downtown” sections."
- 2 simple past and past participle of undergrind form-of, participle, past
Adjective
- 1 Below the ground; below the surface of the Earth. not-comparable
"There is an underground tunnel that takes you across the river."
- 2 Hidden, furtive, secretive. figuratively
"These criminals operate through an underground network."
- 3 Outside the mainstream, especially unofficial and hidden from the authorities. usually
"underground music"
Adjective
- 1 conducted with or marked by hidden aims or methods wordnet
- 2 under the level of the ground wordnet
Adverb
- 1 Below the ground.
"The tunnel goes underground at this point."
- 2 Secretly.
Adverb
- 1 beneath the surface of the earth wordnet
- 2 in or into hiding or secret operation wordnet
Proper Noun
- 1 The London Underground. UK
"Although some of the stations on ' The Branch ' have not, as yet, suffered any considerable structural alterations, all are now equipped with the familiar Underground type name boards, and as a result the imposing titles of G.N. days have been ruthlessly curtailed."
Synonyms
All synonymsAntonyms
Example
"London is such a large city that visitors must use buses and the underground railway to get about."
Common questions
What is a synonym for "underground"?
Common synonyms include: metro, resistance, subway, subway system, tube, abstruse.
How do you use "underground" in a sentence?
London is such a large city that visitors must use buses and the underground railway to get about.
How do you pronounce "underground"?
Pronounced /ˌʌndəˈɡɹaʊnd/.
Etymology
From Middle English undergrounde (adverb), equivalent to under + ground or under- + ground. Compare Dutch ondergrond, ondergronds, German Untergrund, Danish undergrunds.