density

American  

[den-si-tee] / ˈdɛn sɪ ti /

noun

plural

densities

1. the state or quality of being dense; compactness; closely set or crowded condition.

2. stupidity; slow-wittedness; obtuseness.

3. the number of inhabitants, dwellings, or the like, per unit area.

   The commissioner noted that the population density of certain city blocks had fallen dramatically.

4. Physics. mass per unit volume.

5. Electricity.

   1. the quantity of electricity per unit of volume at a point in space, or the quantity per unit of area at a point on a surface.

   2. current density.

6. the degree of opacity of a substance, medium, etc., that transmits light.

7. Photography. the relative degree of opacity of an area of a negative or transparency, often expressed logarithmically.

8. Computers. a measure of the compactness of data saved on a storage medium, as disk or tape, or displayed on an electronic screen.

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density British  

/ ˈdɛnsɪtɪ /

noun

1. the degree to which something is filled, crowded, or occupied

   high density of building in towns

2. obtuseness; stupidity

3.  ρ.  a measure of the compactness of a substance, expressed as its mass per unit volume. It is measured in kilograms per cubic metre or pounds per cubic foot See also relative density

4. a measure of a physical quantity per unit of length, area, or volume See charge density current density

5. physics photog See transmission density reflection density

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density Scientific  

/ dĕn′sĭ-tē /

1. A measure of the quantity of some physical property (usually mass) per unit length, area, or volume (usually volume).

2. ◆ Mass density is a measure of the mass of a substance per unit volume. Most substances (especially gases such as air) increase in density as their pressure is increases or as their temperature decreases.

3. ◆ Energy density is a measure of the amount of energy (often in the form of electromagnetic radiation) per unit volume in a region of space or some material.

4. See also Boyle's law

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density Cultural  

1. The relative heaviness of objects, measured in units of mass or weight per units of volume. (See specific gravity.)

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Other Word Forms

• nondensity noun
• superdensity noun

Etymology

Origin of density

First recorded in 1595–1605; from Latin dēnsitās, equivalent to dēns(us) dense + -itās -ity

Example Sentences

More than 200 hospital patients will be called for a repeat scan to test their bone density after an independent review of patient notes by specialist consultants, the Government of Jersey has said.

From BBC • Apr. 2, 2026

But that same density can tip the cake toward heaviness — toward something that eats more like dessert than companion.

From Salon • Mar. 31, 2026

There is some limited data suggesting that gene-therapy-boosted follistatin levels can have a positive effect on muscle mass and bone density in rodents.

From Slate • Mar. 30, 2026

This month the news broke that CATL, which commands nearly 40% of the global market, had filed a detailed patent application for solid-state batteries with the World Intellectual Property Organization, with a reported 500Wh density.

From The Wall Street Journal • Mar. 28, 2026

If the density is greater than the critical value, gravity will stop the expansion at some time in the future and cause the universe to recollapse.

From "A Brief History of Time: And Other Essays" by Stephen Hawking

Related Words

• frequency
• quantity
• thickness