18-wheeler

Alternative forms

Origin

From the total number of wheels: two front steering wheels on the tractor, plus dual wheels on each end of two axles (total of 8) at the rear of the tractor and supporting the front of the trailer, plus dual wheels on two axles at the rear of the trailer.

Full definition of 18-wheeler

Noun

1. A big rig truck: a semi-trailer plus the truck or tractor pulling it.

Synonyms

• artic
• articulated lorry
• big rig
• juggernaut
• semi
• semi-trailer truck
• tractor-trailer
• truck and trailer