trailer truck vs trucking rig

trailer truck and trucking rig both are nouns.

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

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

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

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

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