Terms Used In New Hampshire Revised Statutes 259:109

• Semi-trailer: shall mean a vehicle of the trailer type so designed and used in conjunction with a self-propelled vehicle that a considerable part of its own weight or that of its load rests upon and is carried by the towing vehicle, and not including a pair or set of wheels commonly used as an implement for other purposes than transportation, provided, however, that the word "semi-trailer" shall not include any vehicle as described in this section if used exclusively for agricultural purposes unless said vehicle be of the type constructed specifically to be towed by a tractor-type truck. See New Hampshire Revised Statutes 259:98
• Truck-tractor: shall mean any vehicle designed and intended primarily for drawing other vehicles and not so constructed as to carry a load other than a part of the vehicle and load so drawn, except that a truck-tractor engaged in the transportation of automobiles may transport motor vehicles on a part of the power unit. See New Hampshire Revised Statutes 259:116