Source : Webster's Revised Unabridged Dictionary (1913)

Pampas \Pam"pas\, n. pl. [Sp., fr. Peruv. pampa a field, plain.]
   Vast plains in the central and southern part of the Argentine
   Republic in South America. The term is sometimes used in a
   wider sense for the plains extending from Bolivia to Southern
   Patagonia.

   {Pampas cat} (Zo["o]l.), a South American wild cat ({Felis
      pajeros}). It has oblique transverse bands of yellow or
      brown. It is about three and a half feet long. Called also
      {straw cat}.

   {Pampas deer} (Zo["o]l.), a small, reddish-brown, South
      American deer ({Cervus, or Blastocerus, campestris}).

   {Pampas grass} (Bot.), a very tall ornamental grass
      ({Gynerium argenteum}) with a silvery-white silky panicle.
      It is a native of the pampas of South America.

Source : WordNet®

pampas
     n : the vast grassy plains of northern Argentina