The quantity of an element whose weight in grams is numerically equal to the atomic weight of the element.
The quantity of an element having a weight in grams numerically equal to the element's atomic weight: a gram atom of copper, the atomic weight of which is 63.54, is a quantity of copper weighing 63.54 grams.
Gram atomic mass is the mass in grams of one mole of atoms in a monoatomic element. or the atomic mass of an element expressed in grams is called gram atomic mass. For example, Nitrogen is 14 grams. The quantity of the element which weighs equal to its gram atomic mass is called the one gram atom of that element.
If we take the mass in grams of any substance which is equal to its atomic mass is the gram atom of that element. For example, 12 grams of carbon is one gram atom of carbon.