If you day trade or trade the lower time frames you should know about this concept. It will save you a lot of lost pips.
Density is Defined as following in general terms
1. the degree of compactness of a substance.
"a reduction in bone density"
synonyms: solidity, solidness, denseness, thickness, substance, bulk, weight, mass; More
IN COMPUTING it means:
a measure of the amount of information on a storage medium.
noun: packing density; plural noun: packing densities
"a low-density floppy disk"
In PHYSICS it means:
the quantity of mass per unit volume of a substance.
the opacity of a photographic image.
the quantity of people or things in a given area or space.
"areas of low population density"
In Trading it means:
Density means the quantity of pips within a candle or a given chart space. In general the higher the time frame the higher the density.