1. density
Wikipedia definition
2. DensityThe mass density or density of a material is defined as its mass per unit volume. The symbol most often used for density is ρ (the lower case Greek letter rho). In some cases (for instance, in the United States oil and gas industry), density is also defined as its weight per unit volume; although, this quantity is more properly called specific weight. Different materials usually have different densities, so density is an important concept regarding buoyancy, purity and packaging.
Read “Density” on English Wikipedia
Read “密度” on Japanese Wikipedia
Read “Density” on DBpedia


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