Source : Webster's Revised Unabridged Dictionary (1913)

Documentary \Doc`u*men"ta*ry\, a.
   Pertaining to written evidence; contained or certified in
   writing. ``Documentary evidence.'' --Macaulay.

Source : WordNet®

documentary
     adj : relating to or consisting of or derived from documents [syn:
            {documental}]

documentary
     n : a film or TV program presenting the facts about a person or
         event [syn: {docudrama}, {documentary film}, {infotainment}]