motortruck vs tip truck

motortruck and tip truck both are nouns.

Word	Noun	Adjective	Verb	Adverb
motortruck	Yes	No	No	No
tip truck	Yes	No	No	No

As nouns, tip truck is a hyponym of motortruck; that is, tip truck is a word with a more specific, narrower meaning than motortruck:

motortruck: an automotive vehicle suitable for hauling
tip truck: truck whose contents can be emptied without handling; the front end of the platform can be pneumatically raised so that the load is discharged by gravity

motortruck (noun)	tip truck (noun)
an automotive vehicle suitable for hauling	truck whose contents can be emptied without handling; the front end of the platform can be pneumatically raised so that the load is discharged by gravity