1. A large truck with multiple axles, typically consisting of a tractor unit (cab) and one or more trailers, used for long-distance freight transportation
The big rig barreled down the highway at dawn.
O caminhão articulado descia pela rodovia ao amanhecer.
2. Any large heavy-duty truck or semi-truck used in commercial transportation
He's been driving a big rig for twenty years.
Ele tem dirigido um caminhão articulado por vinte anos.