Density
Density (den"si*ty) , noun
[Latin densitas; compare French densité.]
1.
The quality of being dense, close, or thick; compactness; -- opposed to rarity.
2.
(Physics) The ratio of mass, or quantity of matter, to bulk or volume, esp. as compared with the mass and volume of a portion of some substance used as a standard.
For gases the standard substance is hydrogen, at a temperature of 0° Centigrade and a pressure of 760 millimeters. For liquids and solids the standard is water at a temperature of 4° Centigrade. The density of solids and liquids is usually called specific gravity, and the same is true of gases when referred to air as a standard.
3.
(Photography) Depth of shade. — Abney