beholding vs fusion

beholding and fusion both are nouns.

Word	Noun	Adjective	Verb	Adverb
beholding	Yes	No	No	No
fusion	Yes	No	No	No

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

beholding: perception by means of the eyes
fusion: the combining of images from the two eyes to form a single visual percept

Other hyponyms of beholding include contrast, face recognition, object recognition, visual space, optical fusion.

beholding (noun)	fusion (noun)
perception by means of the eyes	the act of fusing (or melting) together
	correction of an unstable part of the spine by joining two or more vertebrae; usually done surgically but sometimes done by traction or immobilization
	the combining of images from the two eyes to form a single visual percept
	an occurrence that involves the production of a union
	a nuclear reaction in which nuclei combine to form more massive nuclei with the simultaneous release of energy
	the merging of adjacent sounds or syllables or words
	the state of being combined into one body