What is the Meaning & Definition of molecular weight

From latin pensum ('balancing'), the weight is the force with which the Earth attracts a body. The term is also used to denote the magnitude of this force. The mass, on the other hand, is the physical quantity that expresses the amount of matter contained in a body. This is what distinguishes the weight and mass. The mass is dependent on nor the position of the body in space and gravitation. The kilogram and newton are the units in the international system of units that correspond to the weight and mass, respectively.
This distinction between these two concepts is that the concept of molecular weight is unclear. More correct is to speak to molecular weight, a quantity that is measured in Atomic mass units (AMU).
It is worth mentioning that a molecule is the smallest particle with all the physical and chemical properties of a substance, composed of one or two atoms.
The molecular mass is thus the result of the sum of the Atomic masses of the elements which formed a molecule. In this sense, the relative molecular mass indicates how many times the mass of a molecule of a substance is greater than the unit of atomic mass.
To calculate the molecular weight, it must consider the molecular formula of the compound and the atomic weights of the elements of which they are composed, and multiply each atomic weight by the index that corresponds to the item on the basis of its molecular formula.