(a) The term “lessee” refers not only to lessees under oil and gas leases but also to the owners of unleased lands or mineral rights having the right to develop the same for oil and gas.

(b) Any reference to a separately-owned tract, although in general terms broad enough to include the surface and all underlying common sources of supply of oil and gas shall have reference thereto only in relation to the common source of supply or portion thereof embraced within the unit area of a particular unit.

(c) The phrase “oil and gas” shall refer not only to oil and gas as such in combination one with the other, but shall have general reference to oil, gas, casinghead gas, casinghead gasoline, gas distillate, or other hydrocarbons, or any combination or combinations thereof, which may be found in or produced from a common source of supply of oil, oil and gas or gas distillate.

(d) The term “person” shall mean and include any individual, corporation, partnership, common law or statutory trust, association of any kind, the State of Oklahoma or any subdivision or agency thereof acting in a proprietary capacity, guardian, executor, administrator, fiduciary of any kind, or any other entity or being capable of owning an interest in and to a common source of supply of oil and gas.

(e) The term “unit expense” shall include and mean any and all cost, expense, or indebtedness incurred by the unit in the establishment of its organization, or incurred in the conduct and management of its affairs or the operations carried on by it.