density
n. C / Un. how much mass or how many things are packed into a certain amount of space. If something has high density, it is very heavy for its size or very crowded.
n. the degree of compactness of a substance or population. In physics, it refers to mass per unit volume; in social sciences, it refers to the number of individuals per unit area.
Lead has a much higher density than wood.
The city center has a high population density because thousands of people live in a very small area.
By measuring the density of the unknown liquid and comparing it to known values, the chemist was able to identify the substance as pure ethanol.
Borrowed from Middle French densité or Latin densitas. Morphologically dense + -ity.
Uncountable when referring to the general property of being dense; countable when referring to a specific measurement or mathematical value.