Yes, mass has mass. It is, therefore, matter. If mass did not have mass, then it is "something" with no mass. That would make it "non-matter" and perhaps it might be energy.
source of the word is from India Hindi ḍi·gī, variant of ḍe·gī, ḍe·gā, float, raft.
Large number of people
Mass and mass are the same thing.
The atomic mass number is the mass of the isotope of an element (the sum of number of protons and number of neutrons).