Source : Webster's Revised Unabridged Dictionary (1913)

Adios \A`dios"\, interj. [Sp., fr. L. ad to + deus god. Cf.
   {Adieu}.]
   Adieu; farewell; good-by; -- chiefly used among
   Spanish-speaking people.

   Note: This word is often pronounced [*a]*d[=e]"[-o]s, but the
         Spanish accent, though weak, is on the final syllable.

Source : WordNet®

adios
     n : a farewell remark; "they said their good-byes" [syn: {adieu},
          {arrivederci}, {auf wiedersehen}, {au revoir}, {bye}, {bye-bye},
          {cheerio}, {good-by}, {goodby}, {good-bye}, {goodbye}, {good
         day}, {sayonara}, {so long}]