Source : Webster's Revised Unabridged Dictionary (1913)

Guanaco \Gua*na"co\ (gw[.a]*n[aum]"k[-o]), n.; pl. {Guanacos}
   (-k[=o]z). [Sp. guanaco, Peruv. huanacu. Cf. {Huanaco}.]
   (Zo["o]l.)
   A South American mammal ({Auchenia huanaco}), allied to the
   llama, but of larger size and more graceful form, inhabiting
   the southern Andes and Patagonia. It is supposed by some to
   be the llama in a wild state. [Written also {huanaco}.]