(a) The term "rate", when used in this act, shall mean and include, in the plural number, as well as in the singular, every individual or joint rate, classification, fare, toll, charge or other compensation for service rendered or to be rendered by any public utility, and every rule, regulation, practice, act, requirement or privilege in any way relating to such rate, fare, toll, charge or other compensation, and any schedule or tariff or part of a schedule or tariff thereof.
(b) The term "service regulation" shall mean and include every rule, regulation, practice, act or requirement in any way relating to the service or facilities of a public utility.