agreement vs concession

agreement and concession both are nouns.

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

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

agreement (noun)	concession (noun)
compatibility of observations	a contract granting the right to operate a subsidiary business
the thing arranged or agreed to	a point conceded or yielded
the verbal act of agreeing	the act of conceding or yielding
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