Other forms: documents, documented, documenting
A document is a paper or file that records information officially. A contract, a passport, a report with a reference number.
The word implies a certain formality, which is why nobody calls a shopping list a document. Computing took it over completely, and a document is now any file you make in a word processor. As a verb, stressed on the last syllable, it means to record something in detail, so a well-documented case is one with plenty of evidence behind it. A documentary is a film that does the same job.
Latin
documentum
Middle French
document
English, today
document
Borrowed from Middle French document, from Latin documentum. Middle French document, from Latin documentum.
Etymology from Wiktionary, CC BY-SA