A "single-axle" refers to a type of vehicle or trailer that has only one axle, which is a rod or shaft that connects two wheels. This design is commonly found in smaller trailers, such as utility trailers or some types of campers. Single-axle setups are generally lighter and easier to maneuver compared to their multi-axle counterparts. Single-axle vehicles are often used for transporting lighter loads, making them suitable for personal use or small businesses. They can be towed by various vehicles, including cars and trucks, and are popular for their simplicity and cost-effectiveness in both purchase and maintenance.