volume vs dollar volume

volume and dollar volume both are nouns.

Word	Noun	Adjective	Verb	Adverb
volume	Yes	No	No	No
dollar volume	Yes	No	No	No

As nouns, dollar volume is a hyponym of volume; that is, dollar volume is a word with a more specific, narrower meaning than volume:

Other hyponyms of volume include turnover.

volume (noun)	dollar volume (noun)
physical objects consisting of a number of pages bound together	the volume measured in dollars
the magnitude of sound (usually in a specified direction)
the property of something that is great in magnitude
a publication that is one of a set of several similar publications
the amount of 3-dimensional space occupied by an object
a relative amount