English Reference

Word

dense

US/ˈdɛns/

UK/dˈɛns/

Definitions

01packed together

B2 · Upper Intermediate

adj. having parts that are very close together with little space between them.

adj. characterized by a high degree of compactness or a high ratio of mass to volume.

“The hikers struggled to walk through the dense forest because the trees were so close together.”

“The city's dense urban core presents significant challenges for planners attempting to integrate new green spaces without displacing existing residents.”

Antonyms

02difficult to understand

C1 · Advanced Academic

adj. containing a lot of information or difficult ideas that make it hard to read or follow.

adj. intellectually challenging due to a high concentration of complex ideas or obscure language.

“I found the first chapter of the philosophy book very dense and had to read it twice.”

“The report was so dense with technical jargon and statistical data that even the experts struggled to extract a clear policy recommendation.”

Antonyms

03mathematical sets

C2 · Proficiency Mathematics Technical

adj. used in math to describe a set where you can always find a point between any two other points.

adj. describing a subset of a topological space whose closure is the space itself; every point in the space is a limit point of the set.

“The teacher explained that rational numbers are dense because there is always another fraction between any two.”

“In any interval of the real line, the set of rational numbers is dense, ensuring that any real number can be approximated by a sequence of rationals.”

04slow to understand

B2 · Upper Intermediate Informal

adj. a slightly rude way to describe someone who does not understand things quickly.

adj. exhibiting a lack of mental agility or failing to grasp obvious points; slow-witted.

“I felt a bit dense when I realized the answer was right in front of me the whole time.”

“He was usually quite sharp, but he seemed uncharacteristically dense when we tried to explain the new office procedures to him.”

Synonyms

Antonyms

Collocations

Common phrases and expressions where native English speakers use the word “dense” in context.

Verb

01. become dense

“As the liquid cools, it will become more dense and eventually solidify.”

verb + adj

02. remain dense

“Despite urban development, the central park has managed to remain a dense woodland area.”

verb + adj

Adjective

03. dense forest

“The hikers struggled to navigate through the dense forest due to the thick undergrowth.”

adj + noun

04. dense population

“The city's dense population has led to a significant shortage of affordable housing.”

adj + noun

05. dense with information

“The textbook is dense with information, making it an excellent resource for advanced students.”

adj + prep

06. incredibly dense

“The academic paper was incredibly dense, requiring several readings to fully grasp the argument.”

adv + adj

Noun

07. dense fog

“Flights were delayed for hours as a dense fog descended upon the airport runway.”

adj + noun

08. dense smoke

“Firefighters wore oxygen masks to breathe while moving through the dense smoke.”

adj + noun

09. dense gas

Real-World Examples

“These blooms can become so dense that they change the colour of the lake and seas.”
The Guardian 14 Aug 2026
“The AMOC depends on dense water sinking in the high North Atlantic.”
BBC News 14 Jul 2026

Etymology

From Middle French dense, from Latin dēnsus, from Proto-Indo-European *dens- (“thick, dense”) (whence also Ancient Greek δασύς (dasús)).

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

Word family

ADJECTIVE

dense(C1)

Domain

Mathematics

This entry

Exam level
CambridgeCambridgeCambridge English QualificationsThe exam suite from Cambridge University Press & Assessment, from A1 Movers up to C2 Proficiency. The benchmark names double as CEFR labels.C1 AdvancedIELTSIELTSInternational English Language Testing SystemThe 0–9 band test co-owned by the British Council, IDP, and Cambridge. Used for university entry, work, and migration.7.0–8.0TOEFL iBTTOEFL iBTTest of English as a Foreign Language, Internet-Based TestETS's academic English test, the standard route for US university admissions. Scored 0–120, with a 1–6 scale since 2026.1–6 scale: 5.0–5.595–113TOEICTOEICTest of English for International CommunicationETS's workplace English test, big in Japan and Korea. Listening & Reading scores 10–990 and tops out at C1.945–990
Frequency
Frequent
Level
C1 · AdvancedOxford
Updated

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English Reference