watertube vs tubing

watertube and tubing both are nouns.

Word	Noun	Adjective	Verb	Adverb
watertube	Yes	No	No	No
tubing	Yes	No	No	No

As nouns, tubing is a hypernym of watertube; that is, tubing is a word with a broader meaning than watertube:

watertube: a boiler tube through which the water flows.
tubing: conduit consisting of a long hollow object (usually cylindrical) used to hold and conduct objects or liquids or gases

Other hypernyms of watertube include tube.

watertube (noun)	tubing (noun)
a boiler tube through which the water flows.	conduit consisting of a long hollow object (usually cylindrical) used to hold and conduct objects or liquids or gases