How's this...? "A work, such as a film or television program,
presenting political, social, or historical subject matter in a
factual and informative manner and often consisting of actual news
films or interviews accompanied by narration."
Actually, got this at www.dictionary.com
. And it's about 20 years
out of date!
Today, it's more like... a story with a sweeping dramatic arc,
featuring fascinating characters in a highly unusal situation of great
conflict, where the filmmakers had complete access at all times.
Sound like fiction films? Well, check out the HBO schedule sometime.