trucking rig vs trailer truck

trucking rig and trailer truck both are nouns.

Word	Noun	Adjective	Verb	Adverb
trucking rig	Yes	No	No	No
trailer truck	Yes	No	No	No

As nouns, trucking rig and trailer truck are synonyms defined as:

trucking rig and trailer truck: a truck consisting of a tractor and trailer together

Other synonyms of trucking rig include articulated lorry, rig, semi, tractor trailer.

trucking rig (noun)	trailer truck (noun)
a truck consisting of a tractor and trailer together	a truck consisting of a tractor and trailer together