blend vs harmonize

blend is a noun but harmonize is not a noun.

Word	Noun	Adjective	Verb	Adverb
blend	Yes	No	Yes	No
harmonize	No	No	Yes	No

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

Other hypernyms of blend include accord, agree, concord, consort, fit in, harmonise.

blend (noun)	harmonize (noun)
the act of blending components together thoroughly
a new word formed by joining two others and combining their meanings
an occurrence of thorough mixing

blend (verb)	harmonize (verb)
mix together different elements	bring into consonance, harmony, or accord while making music or singing
combine into one	bring into consonance or accord
blend or harmonize	bring (several things) into consonance or relate harmoniously
	sing or play in harmony
	write a harmony for
	go together