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.
atomic mass - (chemistry) the mass of an atom of a chemical element expressed in atomic mass units. atomic weight, relative atomic mass. mass - the property of a body that causes it to have weight in a gravitational field. combining weight, eq, equivalent weight, equivalent - the atomic weight of an element that has the same combining capacity as a given weight of another element; the standard is 8 for oxygen.