wot is a charge?

I assume you mean electric charge. We can only define it in operational terms, that is, what it does (or really what we see it do).

Electrons have it.

Protons have it, but a different kind.

We've never found another kind.

The kind associated with the electron neutralizes the kind associated with the proton.

In ordinary circumstances, the charge comes only in multiples of 1,2,3...

Like charges repel and unlike charges attract. This force is the same magnitude for the electron charges as for the proton charges. The force is directly proportional to the multiple of charge.

Charge interacts with/by electromagnetic fields.

The unit of electrical charge is the coulomb (named after Charles Coulomb who was the first to make careful quantitative measurements of the force between two charges).

Two small, identically charged particles which are separated by one meter in a vacuum and repel each other with a force of 10^-7c² newtons possess an identical charge of either plus or minus one coulomb. Where c = the velocity of light (2.99796 x 10⁸ m/sec). On that basis, the charge of an electron is a negative 1.60206 x 10^-19 coulomb, and one negative coulomb therefore represents the combined charge of about 6.24 x 10¹⁸ electrons.

The symbol Q is generally used to represent charge that does not vary with time and q or more properly q(t) to represent time-varying charge.

I hope this definition is precise enough for your purposes.

Very generally, a "charge" is the electrical potential difference between the object of concern and some other object or objects of concern. When we say that one carries a charge, we mean that the one has a potential difference from other objects in the area.

If I charge a balloon by rubbing it on my wool sweater, it will have an electrical potential different from other objects and especially the earth. If I place it on the wall the static charge is what will cause the baloon to cling to the wall. When the charge is disapated, the potential equalizes between the wall and the balloon, the balloon falls to the floor.

Not knowing where you are comming from or going to, I avoided explanations having to do with electron orbits, which of course may be exactly what you are asking. ;)

Vishmastar,

Nobody knows what charge is; we only know what charge does.