harmony vs agreement

harmony and agreement both are nouns.

Word	Noun	Adjective	Verb	Adverb
harmony	Yes	No	No	No
agreement	Yes	No	No	No

As nouns, agreement is a hypernym of harmony; that is, agreement is a word with a broader meaning than harmony:

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

harmony: a harmonious state of things in general and of their properties (as of colors and sounds); congruity of parts with one another and with the whole
agreement: harmony of people's opinions or actions or characters

Other hyponyms of harmony include peace, comity, accord.

harmony (noun)	agreement (noun)
an agreeable sound property	compatibility of observations
compatibility in opinion and action	the thing arranged or agreed to
agreement of opinions	the verbal act of agreeing
the structure of music with respect to the composition and progression of chords	the statement (oral or written) of an exchange of promises
a harmonious state of things in general and of their properties (as of colors and sounds); congruity of parts with one another and with the whole	the determination of grammatical inflection on the basis of word relations
	harmony of people's opinions or actions or characters