Okla. Stat. tit. 68 § 5306
When used in this act, the terms "automobile", "truck", "manufactured home", "travel trailer" and "motorcycle" shall have the meanings as same are respectively defined in the Oklahoma Vehicle License and Registration Act, and the terms "new automobile", "new truck", "new motorcycle", "new manufactured home" and "new recreational vehicle" shall be given the same meaning as the term "new vehicle" is defined in the Oklahoma Vehicle License and Registration Act. Vessel and motors shall have the same meanings as in the Oklahoma Vessel and Motor Registration Act. The term "truck" shall also include truck-tractors and farm trucks, but this act shall not be construed as relieving or exempting from ad valorem taxation the inventory of dealers in special mobilized machinery, motor homes or any other similar self-propelled vehicles.
Okla. Stat. tit. 68, § 5306