393.410.  Definitions. — As used in sections 393.410 to 393.510:

  (1)  "Gas" means manufactured or natural gas or any combination or mixture thereof, whether or not the natural gas has been processed by removal of component parts not essential to its use for light, heat, or power;

  (2)  "Gas storage company" means any corporation, partnership or person, or its trustees or receivers appointed by any court whatsoever, including any municipal corporation, any gas corporation as defined by section 386.020, and any corporation engaged in the transportation of natural gas in interstate commerce or the sale in interstate commerce of such gas for resale, engaged in or which desires to engage in the business of the underground storage of gas intended in whole or in part for either direct or ultimate distribution to the public by means of pipes or pipelines;

  (3)  "Underground storage" or "underground storage of gas" means the storing of gas in a geological stratum or strata, formation or formations lying beneath the surface of the earth;

  (4)  "Underground storage reservoir" means the stratum or strata, formation or formations which are, or are to be, used for underground storage of gas.