And I said:

"The inertia of an object, [i.e.] how easy or hard it is to change its motion, ..."

That's a definition of inertia; and:

"its mass which is abbreviated by the symbol "m" and is measured in kilograms ..."

That's referring to _mass_ and the unit in which _mass_ is measured.

So there!!! ;-)

Seriously guys, let's remember that we're trying to clarify some pretty non-intuitive ideas for Kim here. Let's save the subtleties for Physics 201!!