documentary

adj

1. (not-comparable)Of, related to, or based on documents.
2. (not-comparable)Which serves to document (record or illustrate) a subject.
3. (not-comparable)Presented objectively without the insertion of fictional matter.

   “a documentary film”

   “Just as there is a tradition of history painting, so there is one of history photographs — which of course are not documentary. They're posed as the world was supposed to be.”

noun

1. (countable, uncountable)A film, TV program, publication etc. which presents a social, political, scientific or historical subject in a factual or informative manner.

   “Fifteen documentaries are in sharp-elbowed competition to be among the five Oscar nominees.”

   “If you watched Victoria Beckham’s lavishly produced Netflix documentary last October, you might have wondered why it didn’t even glance on the biggest elephant in Brand Beckham’s room[…]. But most big documentaries these days aren’t documentaries any more in the way previous practitioners of the craft might have understood the word. As her husband’s was before it, Victoria’s doc was a self-commissioned advertorial on which the subject also served as executive producer.”

2. (uncountable)Such works collectively, as a genre.

   “Such sequences draw attention to the affective appeals that environmental documentary typically makes, precisely by absenting those appeals.”