2.10  Mass and Weight

Mass  is the property of matter that manifests itself as inertia and may be thought of as the quantity of matter in the body. The unit of mass is the kilogram (kg).  The corresponding English unit is the pound. 

Weight is the force of gravity upon the mass.  When asked for our weight, we typically respond with our mass (73 kg) because the force of gravity is pretty much the same everywhere on earth.  The real units for weight are the Newton N.    ( My real weight would be 73 kg *9.8m/s²).  Remember F=ma.