Question

What is Relative atomic mass

Answer 1

This is the atomic mass which is measured relative to any other element.
Hydrogen has atomic mass 1u.
Relative to Hydrogen, Calcium has atomic mass 40u.
Similarly, Carbon has atomic mass 12u and so on.

Answer 2

atomic masses

the ratio of the average mass of one atom of an element to one twelfth of the mass of an atom of carbon-12.