Density (disambiguation)

Density and dense usually refer to a measure of how much of some entity is within a fixed amount of space. Types of density include:

Density of mass

 * Density, mass per unit volume
 * Bulk density, mass of a particulate solid or powder divided by the volume it occupies
 * Particle density (packed density) or true density, density of the particles that make up a particulate solid or a powder
 * Neutral density, mass density of seawater
 * Area density or surface density, mass over a (two-dimensional) area
 * Linear density, mass over a (one-dimensional) line
 * Relative density or specific gravity, a measure of density in comparison to the density of something else
 * Vapour density, a relative density used for gases

Densities of other entities

 * Mass-specific quantity, the quotient of a physical quantity and mass
 * Specific energy, energy per unit mass


 * Volume-specific quantity, the quotient of a physical quantity and volume
 * Charge density, the electric charge per volume
 * Energy density, potential energy per unit volume
 * Force density, force per unit volume
 * Power density, power per unit volume
 * Particle density (particle count), number of particles per unit volume


 * Area-specific quantity, the quotient of a physical quantity and area
 * Current density, the ratio of electric current to area
 * Surface power density, power per unit area

Other:
 * Number density, number of particles per unit volume, area, or length
 * Optical density, the absorbance of a material
 * Densitometry, measuring the optical density of photographic paper, photographic film and x-ray film

Probability and measure theory

 * Probability density function, a function which maps probabilities across the real line and whose integral is 1
 * Density estimation is the construction of an estimate of a probability density function
 * Kernel density estimation, used in statistics to estimate a probability density function of a random variable
 * Lebesgue's density theorem

Number theory

 * Schnirelmann density
 * Natural density (also called asymptotic density)
 * Dirichlet density

Geometry

 * Packing density
 * Density (polytope)
 * Density on a manifold
 * Tensor density in differential geometry

Topology

 * Dense set and nowhere dense set
 * Dense-in-itself is a set that contains no isolated points

Other fields

 * Density (graph theory), the fraction of possible edges that exist in a graph
 * Dense order in order theory
 * A coinitial subset in the mathematical theory of forcing, in set theory
 * Dense submodule in abstract algebra

Other scientific fields

 * Population density, population per unit land area
 * Urban density, in urban planning and urban design
 * Areal density (computer storage), bits (how computers store information) over an amount of area or volume
 * Nutrient density, the proportion of any array of a single nutrient or nutritional factor, or of numerous nutrients in foods, often ordered by different scalar indices

Culture and arts

 * Stupidity, a stupid person is sometimes referred to as being "dense"
 * Dense (film), a 2004 film
 * Density 21.5 – a piece of music for solo flute written by Edgard Varèse