com·men·tar·y 
(kŏmən-tĕr′ē)
(kŏmən-tĕr′ē)n. pl. com·men·tar·ies
1.
a. Explanation or interpretation in the form of a series of comments or observations: "The Spectator was a widely appreciated model of urbane social commentary mingled with popularized philosophy" (Leo Damrosch).
b. An ongoing series of spoken remarks, especially during a television or radio broadcast of an event: Two retired players did the commentary for the game.
2. An apt explanation or illustration: a scandal that is a sad commentary on national politics.
3. often commentaries
a. An expository treatise or series of annotations; an exegesis: a commentary on Plato's Republic; biblical commentaries.
b. A narrative of historical events of which one has personal experience: Caesar's commentaries on the war in Gaul.
com′men·tari·al (-târē-əl) adj.