den·​si·​ty | \ ˈden(t)-sə-tē How to pronounce density (audio) \
plural densities

Definition of density

1 : the quality or state of being dense measures of traffic density the density of the cake felt that the candidate's density on the subject of equality was alarming the density of her prose
2 mathematics : the quantity per unit of volume (see volume entry 1 sense 2), unit of area (see area sense 1), or unit of length: such as
a chemistry : the mass (see mass entry 2 sense 1c) of a substance per unit of volume pure iron has a density of 7.8 grams per cubic centimeter
b chemistry : the distribution of a quantity (such as electricity or energy) per unit usually of space (such as length, area, or volume) The drawback to using ethanol as a complete replacement for gasoline, however, is not only the high cost of its production from cellulose but also its lower energy density.— John R. Regalbuto
c : the average number of individuals or units per unit of space a population density of 500 per square mile a housing density of 10 houses per acre
3 physics
a : the degree of opacity (see opacity sense 2) of a translucent medium the fog's density
b : the common logarithm of the opacity

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Examples of density in a Sentence

We were surprised by the fog's density. the density of her writing style These instruments are used for measuring the density of the atmosphere.
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Recent Examples on the Web Oh, air still has the same density for both objects. Rhett Allain, Wired, "How to Calculate the String Angle of a Kite vs. a Balloon," 15 Feb. 2021 If your screen has a high-pixel density, then a higher DPI might be helpful. Carsen Joenk, Popular Science, "Best gaming mouse: What to look for when buying this accessory," 11 Dec. 2020 Cruise likes to emphasize that San Francisco, where its cars operate, has a high density of pedestrians, bicyclists, and strangely parked vehicles. Timothy B. Lee, Ars Technica, "Cruise says it has started driverless testing—I’m skeptical," 9 Dec. 2020 Fractures in adulthood and older ages are common, but previous studies have shown that vegetarians have lower bone mineral density than non-vegetarians. Kristen Rogers, CNN, "Vegans may be at higher risk for bone fractures, study finds," 22 Nov. 2020 Those areas often have the lowest population density. Washington Post, "Trump wasn’t just a rural phenomenon. Most of his supporters come from cities and suburbs.," 17 Nov. 2020 City staff noted the Naperville City Council allowed CityGate Centre to have a density of 773 square feet per dwelling unit or 56.4 dwelling units per acre. Suzanne Baker,, "CityGate West opponents say the proposed hotels are too small, apartment complex too big," 17 Nov. 2020 The lawsuit, which was withdrawn on Monday, alleged that Sacred Heart approved the contest despite knowing the dangers of choking since pancakes have a thick density. Mica Soellner, Washington Examiner, "Connecticut school settles suit over student's death in pancake-eating contest," 14 Nov. 2020 While habitat loss writ large presents a threat, Hannah calls specific attention to forests, which have a high density of biodiversity and therefore present more opportunities for disease carriers. Sarah Gibbens, National Geographic, "Protecting land and animals will mitigate future pandemics, report says," 29 Oct. 2020

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'density.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of density

1598, in the meaning defined at sense 1

History and Etymology for density

see dense

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Time Traveler for density

Time Traveler

The first known use of density was in 1598

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Statistics for density

Last Updated

26 Feb 2021

Cite this Entry

“Density.” Dictionary, Merriam-Webster, Accessed 5 Mar. 2021.

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More Definitions for density



English Language Learners Definition of density

: the quality of having parts that are close together
: the quality of being difficult to see through
: the quality of being difficult to understand


den·​si·​ty | \ ˈden-sə-tē How to pronounce density (audio) \
plural densities

Kids Definition of density

1 : the condition of having parts that are close together the jungle's density
2 : the amount of something in a specified volume or area high population density


den·​si·​ty | \ ˈden(t)-sət-ē, -stē How to pronounce density (audio) \
plural densities

Medical Definition of density

1 : the quantity per unit volume, unit area, or unit length: as
a : the mass of a substance per unit volume
b : the distribution of a quantity (as mass, electricity, or energy) per unit usually of space
c : the average number of individuals or units per space unit a population density of 500 per square mile
2a : the degree of opacity of a translucent medium

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