Vehicle is something used as an instrument of conveyance. It can include any conveyance used for transporting passengers or things by land, water, or air. It can be a self propelled conveyance that runs on tires like a motor vehicle.
Vehicle includes any mechanical device on wheels, designed mainly for use, or used, on highways, except motorized bicycles, vehicles propelled or drawn by horses or human power, or vehicles used exclusively on fixed rails or tracks, or cotton trailers or motorized wheelchairs operated by handicapped persons. In re Lund, 2005 Bankr. LEXIS 2643, 1-2 (Bankr. W.D. Mo. Dec. 9, 2005)
Example of state statutes (Texas) defining vehicle.
Tex. Ins. Code § 4055.051 defines vehicle as follows
(4) "Vehicle" means:
(A) a private passenger motor vehicle, including passenger vans and minivans that are primarily intended for the transport of persons;
(B) a motor home;
(C) a motorcycle;
(D) a trailer with a gross vehicle weight rating of 10,000 pounds or less; or
(E) a truck with a gross vehicle weight rating of 26,000 pounds or less and the operation of which does not require a commercial driver's license.
Tex. Health & Safety Code § 386.101 defines motor vehicle as follows:
(3) "Motor vehicle" means a self-propelled device designed for transporting persons or property on a public highway that is required to be registered under Chapter 502, Transportation Code.
Tex. Finance Code § 348.001 defines heavy commercial vehicle as follows:
(2) "Heavy commercial vehicle" means:
(A) a truck or truck tractor that:
(i) has a gross vehicular weight of 19,000 pounds or more; and
(ii) is not used primarily for personal, family, or household use; or
(B) a trailer or semitrailer designed for use in combination with a vehicle described by Paragraph (A).