'tractor-trailer' originates from the combination of 'tractor,' which comes from Latin 'tractus,' meaning 'to pull,' and 'trailer,' from English 'trail,' meaning 'to drag or pull behind.'

'tractor' changed from the Latin word 'tractus' and eventually became the modern English word 'tractor.' 'Trailer' evolved from the English word 'trail.'

Initially, 'tractor' meant 'a machine for pulling,' and 'trailer' meant 'something that trails or is dragged.' Over time, they combined to describe a vehicle used for transporting goods.