Araguay, ah rah gwi', or Araguaya, ah'ragwa yah', a Brazilian river, rising in the Serra Cayapo. It flows north and joins the Tocantins at Sao Joao. About the middle of its course it divides into two arms, enclosing the island of Bananal. The length of the Araguay is 1300 miles, of which 750 are navigable. The lower course has numerous rapids.