sound truck vs truck

sound truck and truck both are nouns.

Word	Noun	Adjective	Verb	Adverb
sound truck	Yes	No	No	No
truck	Yes	No	Yes	No

As nouns, truck is a hypernym of sound truck; that is, truck is a word with a broader meaning than sound truck:

Other hypernyms of sound truck include motortruck.

sound truck (noun)	truck (noun)
a truck equipped with a loudspeaker and used for advertising	an automotive vehicle suitable for hauling
	a handcart that has a frame with two low wheels and a ledge at the bottom and handles at the top; used to move crates or other heavy objects

sound truck (verb)	truck (verb)
	convey (goods etc.) by truck