tank ship vs tanker

tank ship and tanker both are nouns.

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

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

Other synonyms of tank ship include oil tanker, oiler.

tank ship (noun)	tanker (noun)
a cargo ship designed to carry crude oil in bulk	a cargo ship designed to carry crude oil in bulk
	a motor vehicle designed to carry liquefied loads, dry bulk cargo or gases on roads.
	a soldier who drives a tank