tank truck vs tanker truck

tank truck and tanker truck both are nouns.

Word	Noun	Adjective	Verb	Adverb
tank truck	Yes	No	No	No
tanker truck	Yes	No	No	No

As nouns, tank truck and tanker truck are synonyms defined as:

tank truck and tanker truck: a motor vehicle designed to carry liquefied loads, dry bulk cargo or gases on roads.

Other synonyms of tank truck include tanker.

tank truck (noun)	tanker truck (noun)
a motor vehicle designed to carry liquefied loads, dry bulk cargo or gases on roads.	a motor vehicle designed to carry liquefied loads, dry bulk cargo or gases on roads.