Source : Webster's Revised Unabridged Dictionary (1913)

Monumental \Mon`u*men"tal\, a. [L. monumentalis: cf. F.
   monumental.]
   1. Of, pertaining to, or suitable for, a monument; as, a
      monumental inscription.

   2. Serving as a monument; memorial; preserving memory. ``Of
      pine, or monumental oak.'' --Milton.

            A work outlasting monumental brass.   --Pope.

Source : WordNet®

monumental
     adj 1: relating or belonging to or serving as a monument; "the use
            of the arch in monumental architecture"; "monumental
            sculptures"
     2: of outstanding significance; "Einstein's monumental
        contributions to physics"
     3: imposing in size or bulk or solidity; "massive oak doors";
        "Moore's massive sculptures"; "the monolithic proportions
        of Stalinist architecture"; "a monumental scale" [syn: {massive},
         {monolithic}]