trailer truck vs tractor trailer

trailer truck and tractor trailer both are nouns.

Word	Noun	Adjective	Verb	Adverb
trailer truck	Yes	No	No	No
tractor trailer	Yes	No	No	No

As nouns, trailer truck and tractor trailer are synonyms defined as:

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

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

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