density

noun5

1. •
   The amount of a certain phenomenon (such as stuff, things, energy, or otherwise) in a given area (surface area) or volume (amount of space).
2. •
   A measure of the mass of matter contained by a unit volume.
3. •
   The ratio of one quantity, representing something of interest, to another quantity representing space, area, or extent in which the thing of interest is distributed.

   • The number of particles per unit volume of a specified volume can be considered to be the particle density for the specified volume.
4. •
   Stupidity.

   • There's only so much density that pedagogy can penetrate.
5. •
   The probability that an outcome will fall into a given range, per unit of that range; the relative likelihood of possible values of a continuous random variable.