concession vs bye

concession and bye both are nouns.

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

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

concession: the act of conceding or yielding
bye: an automatic advance to the next round in a tournament without playing an opponent

Other hyponyms of concession include pass.

concession (noun)	bye (noun)
a contract granting the right to operate a subsidiary business	a farewell remark
a point conceded or yielded	an automatic advance to the next round in a tournament without playing an opponent
the act of conceding or yielding