(1) "Corporation" means any private corporation, municipal corporation, joint-stock company, partnership, association, business trust, or other organized group of persons, whether incorporated or not, or a receiver or trustee of any of the foregoing.
(2) "Person" means an individual or a corporation.
(3) "Utility" means any person who supplies, furnishes, or sells a utility service.
(4) "Utility service" means gas or electricity which is supplied, sold, or furnished by any person subject to the jurisdiction of the commission.