Question: what is electricity?

Susan Cartwright answered on 23 Jun 2015:

Electricity, as in the stuff that travels through the wires in your house, is the movement of electrons. Electricity in a more general sense is the movement or concentration of electric charge.

To a particle physicist like myself, electricity and magnetism are both aspects of the fundamental force caused by particles exchanging photons (particles of light). Only those particles that possess a property that we call “charge” can do this, and charge comes in two types, which we traditionally call positive and negative. The signs are quite arbitrary: we could have defined the electron charge to be positive instead of negative, if we’d wanted.