amazon : Idioms & Phrases

• noun small reddish slave-making ant species
  Polyergus rufescens.
  

WordNet

• (Zoöl.), a species of ant (Polyergus rufescens), of Europe and America. They seize by conquest the larvæ and nymphs other species and make slaves of them in their own nests.

Webster 1913

• noun a major South American river; arises in the Andes and flows eastward into the South Atlantic; the world's 2nd longest river (4000 miles)
  Amazon.
  

WordNet