noun

1. A series of comments or annotations; especially, a book of explanations or expositions on the whole or a part of some other work

2. (usually in the plural) a brief account of transactions or events written hastily, as if for a memorandum

   “Caesar's Commentaries on the Gallic War”

3. An oral relation of an event, especially broadcast by television or radio, as it occurs

   “We listened to the football commentary while watching the match.”

Synonyms: scholia, secondary source