Home » Training » Trailer Glossary » Bobtail Bobtail In the context of trucking, a bobtail refers to a semi-truck that is operating without a trailer attached. Click to share on Facebook (Opens in new window) Facebook Click to share on X (Opens in new window) X Click to share on Reddit (Opens in new window) Reddit Click to share on Pinterest (Opens in new window) Pinterest Click to share on LinkedIn (Opens in new window) LinkedIn