The mass of a substance per unit volume.
Definition of DENSITY. 1. : the quality or state of being dense. 2. : 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 (as length, area, or volume). 3. Density is defined as how tightly or loosely packed a substance is, or to the number of things or people in a certain area. An example of density is population density, which refers to the number of people in a certain geographic area. This relationship between the mass and volume of a substance is what defines the physical property of density: Density = Mass/Volume. Density is defined as the ratio of an object's mass to its volume, as shown in the equation above. Because it is a ratio, the density of a material remains the same without regard to how much of that material is present. Density is therefore called an intensive property of matter. 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.
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what defines density