All FALSE
When we use the plain term "density", it is understood to mean mass density, or mass/volume. "Charge density" is understood to mean charge/volume. If volume is NOT the denominator, then the convention is to explicitly state the denominator. Thus, "surface charge density" means charge/(surface area). It makes sense to define surface charge density when dealing with a conductor which carries an electrostatic charge, because all of the charge is located on the surface in such cases.