The definition of inbound is something that moves inward. An example of inbound is the freeway that goes toward the city center. 1  traveling or going inward.  Basketball inbounds.
Mass is a measurement of how much matter is in an object. Mass is a combination of the total number of atoms, the density of the atoms, and the type of atoms in an object. How to Measure Mass.
Mass is a scientific term used to describe the density and type of atoms in any given object. The SI unit of mass is the kilogram (kg), though mass can also be measured in pounds (lb). To quickly understand the concept of mass, think of a pillowcase filled with feathers and a similar pillowcase filled with bricks.