dense

American  

[dens] / dɛns /

adjective

denser, densest

1. having the component parts closely compacted together; crowded or compact.

   a dense forest;

   dense population.

   Synonyms:

   impenetrable, teeming

2. stupid; slow-witted; dull.

3. intense; extreme.

   dense ignorance.

4. relatively opaque; transmitting little light, as a photographic negative, optical glass, or color.

5. difficult to understand or follow because of being closely packed with ideas or complexities of style.

   a dense philosophical essay.

6. Mathematics. of or relating to a subset of a topological space in which every neighborhood of every point in the space contains at least one point of the subset.

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dense British  

/ dɛns /

adjective

1. thickly crowded or closely set

   a dense crowd

2. thick; impenetrable

   a dense fog

3. physics having a high density

4. stupid; dull; obtuse

5. (of a photographic negative) having many dark or exposed areas

6. (of an optical glass, colour, etc) transmitting little or no light

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Other Word Forms

• densely
  adverb
• denseness
  noun
• nondenseness
  noun
• superdense
  adjective
• ultradense
  adjective

Etymology

Origin of dense

First recorded in 1590–1600; from Latin dēnsus “thick”; cognate with Greek dasýs

Explanation

When woods are dense, the trees grow close together. When fog is dense, you can't see through it. And if someone calls you dense, they think nothing can get into your thick skull. Dense comes from the Latin densus which means thick and cloudy. In general, the word means packed tight and gives the sense that something is difficult to get through. Text can be dense in two different ways: when the words are packed closely together on the page, and when the text is filled with big words and complicated thoughts. Either way, reading dense text is just no fun.

Example Sentences

Dense breast tissue appears white on a mammogram, the same color as tumors, making it more difficult to detect abnormalities.

From The Wall Street Journal • May 4, 2026

Dense breast tissue like Hamilton’s is a common condition shared by about 40 percent of women who get mammograms, according to the American Cancer Society.

From Slate • Feb. 4, 2026

Dense black smoke rises from the forest as we take off.

From BBC • Feb. 3, 2026

Dr. Maximilian Mahlein, a researcher at Fabbietti's Chair for Dense and Strange Hadronic Matter at the TUM School of Natural Sciences, adds that the findings have broader implications.

From Science Daily • Dec. 27, 2025

Dense thickets of brambles, hawthorn, vines, and trees—called hedgerows—provided perfect hiding places for machine-gun nests.

From "Hitler Youth: Growing Up in Hitler's Shadow" by Susan Campbell Bartoletti

Related Words

• heavy
• impenetrable
• opaque
• solid