Do you know what the physical meaning of the moment of inertia is? I've found that questions like this in a Physics class will almost always be answered with, "It's a collection of symbols we see often enough to give it a special name."
That being said, it's a measurement of the distance between the positive and negative charges in an electric dipole for a simple two charge dipole multiplied by the magnitude of one of the charges. That's a pretty physical meaning for it. It shows up in the math when we ask questions like what kind of Torque does the dipole experience when placed in an electric field. When we crunch the numbers we keep seeing a charge multiplied by a distance and we call it a 'moment' for convenience, because that's what we called it the last time we saw it ; )