Charge and Quanta! One topic that is still ridiculously argued among the brightest minds on earth!
Charge: In simple man terms is the electricity in better manner unbalanced electricity in an object/mass!
Classic definition of Electric Charge:
The quantity of unbalanced electricity in a body (either positive or negative) and construed as an excess or deficiency of electrons.
We have that each atom is made of proton neutron and electron. Proton constitutes the positivity and Electron constitutes for the negativity. I will have a separate post to discuss how charges are determined. Believe me it a little deeper than you think(Sub-atomic Level)!
As you may know for any medium the number of protons and electrons are to be kept the same for it to remain neutral or electrically stable. If we remove an electron / proton then this causes the unbalance. The amount of unbalance si charge and causes the medium to behave as a positive or negative material.