An articulated vehicle is a type of vehicle that consists of a tractor unit and a semi-trailer that are connected by a hinge. This type of vehicle is commonly used for transporting large and heavy goods over long distances. However, there are several other names or synonyms for this type of vehicle, depending on the region or industry. Some of the most common synonyms include semi-truck, semi-trailer truck, tractor-trailer, big rig, and 18-wheeler. Additionally, articulated vehicles may also be referred to as HGVs (heavy goods vehicles) or LGVs (large goods vehicles) in some countries. These synonyms may vary in popularity or usage depending on the context or region.