35 ILCS 173/5-5
For purposes of this Law:
"Delivering supplier" means any person engaged in the business of delivering gas to persons for use or consumption and not for resale, and who, in any case where more than one person participates in the delivery of gas to a specific purchaser, is the last of the suppliers engaged in delivering the gas prior to its receipt by the purchaser. "Delivering supplier maintaining a place of business in this State", or any like term, means any delivering supplier having or maintaining within this State, directly or by a subsidiary, an office, distribution facility, sales office, or other place of business, or any employee, agent, or other representative operating within this State under the authority of such delivering supplier or such delivering supplier's subsidiary, irrespective of whether such place of business or agent or other representative is located in this State permanently or temporarily, or whether such delivering supplier or such delivering supplier's subsidiary is licensed to do business in this State.
"Department" means the Department of Revenue of the State of Illinois.
"Director" means the Director of Revenue.
"Gas" means any gaseous fuel distributed through a pipeline system.
"Person" means any natural individual, firm, trust, estate, partnership, association, joint stock company, joint adventure, corporation, limited liability company, or a receiver, trustee, guardian, or other representative appointed by order of any court, or any city, town, county, or other political subdivision of this State.
"Purchase of out-of-State gas" means a transaction for the purchase of gas from any supplier in a manner that does not subject the seller of that gas to liability under the Gas Revenue Tax Act.
"Purchase price" means the consideration paid for the distribution, supply, furnishing, sale, transportation, or delivery of gas to a person for use or consumption and not for resale, and for all services directly related to the production, transportation, or distribution of gas distributed, supplied, furnished, sold, transmitted, or delivered for use or consumption, including cash, services, and property of every kind and nature. However, "purchase price" shall not include consideration paid for:
In case credit is extended, the amount thereof shall be included only as and when payments are received.
"Purchaser" means any person who acquires the ownership of gas for use or consumption, and not for resale, for a valuable consideration.
"Self-assessing purchaser" means a purchaser of gas for use or consumption that is required to be registered with the Department and is responsible for filing returns and paying the tax imposed under this Law directly to the Department.
"Use" means the exercise by any person of any right or power over gas incident to the ownership of that gas, except that it does not include the sale of gas in the regular course of business.
35 ILCS 173/5-5