semi vs trucking rig

semi and trucking rig both are nouns.

Word	Noun	Adjective	Verb	Adverb
semi	Yes	No	No	No
trucking rig	Yes	No	No	No

As nouns, semi and trucking rig are synonyms defined as:

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

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

semi (noun)	trucking rig (noun)
a trailer having wheels only in the rear; the front is supported by the towing vehicle	a truck consisting of a tractor and trailer together
a truck consisting of a tractor and trailer together
one of the two competitions in the next to the last round of an elimination tournament