Origin: Latin suffix -ary
Documentary has 5 different meanings across 2 categories:
a film or TV program presenting the facts about a person or event
"After watching the new documentary, I was surprised to learn that many of the events in history were actually quite different from what we learned in school."
A film, TV program, publication etc. which presents a social, political, scientific or historical subject in a factual or informative manner.
"After watching the documentary about climate change, I was deeply moved by the real-world data and personal stories presented in the program."
In plain English: A documentary is a non-fiction film that tells a true story about real people or events.
"We watched a fascinating documentary about marine life last night."
Usage: Use documentary to refer specifically to a non-fiction film, television program, or publication that presents real-world subjects like history or science in an informative way. Do not use it as a general synonym for any written record or file; simply call those documents.
relating to or consisting of or derived from documents
"The historian spent weeks cross-referencing conflicting accounts in a new documentary that relied entirely on official government records and private letters."
(of film, television, radio, or photography) depicting a real-life event using images or interviews with people involved in the event
"The new documentary about the historic fire featured exclusive interviews with survivors and grainy footage from the scene."
Of, related to, or based on documents.
"The lawyer argued that the entire case rested on a documentary piece of evidence found in the archives."
In plain English: A documentary is something that shows real events and facts instead of making things up for entertainment.
"The documentary film won several awards at the festival."
Usage: Use "documentary" as an adjective to describe films, plays, or other works that are factual and based on real events rather than fiction. Do not use it when referring strictly to written records, where the noun form is preferred.
The word documentary comes from the French documentaire, which is derived from the Latin documentum meaning "lesson" or "proof." It entered English as a compound of document and the suffix -ary to describe works based on factual evidence rather than fiction.