(n) the amount of some thing per unit measure, especially per device size, location, or amount.
(n) The mass per unit level of a substance under specific problems of force and heat.
Density in Astronomy Dictionary
the actual quantity of matter included within a given volume. Density is calculated in grms per cubic centimeter (or kilograms per liter). The thickness of liquid is 1.0, metal is 7.9, and lead is 11.3. by Leonie LothReport definition