blend in vs fuse

blend in is not a noun while fuse is a noun.

Word	Noun	Adjective	Verb	Adverb
blend in	No	No	Yes	No
fuse	Yes	No	Yes	No

As verbs, fuse is a hypernym of blend in; that is, fuse is a word with a broader meaning than blend in:

Other hypernyms of blend in include blend, coalesce, combine, commingle, conflate, flux, immix, meld, merge, mix.

blend in (noun)	fuse (noun)
	any igniter that is used to initiate the burning of a propellant
	an electrical device that can interrupt the flow of electrical current when it is overloaded

blend in (verb)	fuse (verb)
cause (something) to be mixed with (something else)	mix together different elements
blend or harmonize	make liquid or plastic by heating
	become plastic or fluid or liquefied from heat
	equip with a fuse; provide with a fuse