tractor unit
characteristically heavy-duty towing engine that provides motive power for hauling a towed or trailered load
en-US/ˈtɹæktɚ ˈjunət/
en-GB/ˈtɹæktə ˈjuːnɪt/
characteristically heavy-duty towing engine that provides motive power for hauling a towed or trailered load