The Collaborative International Dictionary of English v.0.48:

Pampero \Pam*pe"ro\, n. [Sp., fr. pampa a plain.]
   A violent wind from the west or southwest, which sweeps over
   the pampas of South America and the adjacent seas, often
   doing great damage. --Sir W. Parish.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Pamperos \Pam*pe"ros\, n. pl.; sing. Pampero. [Sp. American.]
   (Ethnol.)
   A tribe of Indians inhabiting the pampas of South America.
   [1913 Webster]