Pronunciation: (kom'un-ter"ē),[key] —n., —pl.-tar•ies. 1. a series of comments, explanations, or annotations: a commentary on the Bible; news followed by a commentary. 2. an explanatory essay or treatise: a commentary on a play; Blackstone's commentaries on law. 3. anything serving to illustrate a point, prompt a realization, or exemplify, esp. in the case of something unfortunate: The dropout rate is a sad commentary on our school system. 4. Usually, commentaries. records of facts or events: Commentaries written by Roman lawyers give us information on how their courts functioned.