unison vs agreement

unison and agreement both are nouns.

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

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

Other hypernyms of unison include accord.

unison (noun)	agreement (noun)
(music) two or more sounds or tones at the same pitch or in octaves	compatibility of observations
occurring together or simultaneously	the thing arranged or agreed to
corresponding exactly	the verbal act of agreeing
	the statement (oral or written) of an exchange of promises
	the determination of grammatical inflection on the basis of word relations
	harmony of people's opinions or actions or characters