The Collaborative International Dictionary of English v.0.48:

Paisano \Pa`i*sa"no\ (p[aum]`[-e]*s[aum]"n[-o]), n. [Sp., of the
   country, native.]
   1. (Zool.) The chaparral cock; the roadrunner.

   2. A compatriot.
      [PJC]

   3. A comrade; a pal; a buddy.
      [PJC]