Source : Webster's Revised Unabridged Dictionary (1913)

Vegetation \Veg`e*ta"tion\, n. [Cf. F. v['e]g['e]tation, L.
   vegetatio an enlivening. See {Vegetable}.]
   1. The act or process of vegetating, or growing as a plant
      does; vegetable growth.

   2. The sum of vegetable life; vegetables or plants in
      general; as, luxuriant vegetation.

   3. (Med.) An exuberant morbid outgrowth upon any part,
      especially upon the valves of the heart.

   {Vegetation of salts} (Old Chem.), a crystalline growth of an
      arborescent form.

Source : WordNet®

vegetation
     n 1: all the plant life in a particular region [syn: {flora}]
          [ant: {fauna}]
     2: the process of growth in plants
     3: an abnormal growth or excrescence (especially a warty
        excrescence on the valves of the heart)
     4: inactivity that is passive and monotonous, comparable to the
        inactivity of plant life; "their holiday was spent in
        sleep and vegetation"