imaging vs dreaming

imaging and dreaming both are nouns.

Word	Noun	Adjective	Verb	Adverb
imaging	Yes	No	No	No
dreaming	Yes	No	No	No

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

imaging (noun)	dreaming (noun)
(medicine) obtaining pictures of the interior of the body	a series of mental images and emotions occurring during sleep
the ability to form mental images of things or events	imaginative thoughts indulged in while awake