👉 In physics, "massiness" is a concept used to describe an object's level of density. This concept is primarily applied in the study of light and matter. Massiness can be quantified by comparing an object's weight with its weight per unit volume. Objects that are more dense (i.e., have higher mass) tend to weigh less than those that are lighter, indicating their greater massiness. In essence, "massiness" is a measure of the density of an object relative to