Aino, i'no, or Ainu, i'noo, the native name of an uncivilized race of people inhabiting the Japanese island of Yezzo, also Saghalien and the Kurile Islands, and believed by some to be the aboriginal inhabitants of Japan. The Ainos average less than five feet in height, but are strong and active. Their hair is black and covers the whole body and most of the face; in complexion they are dark brown, approaching to black. Their religion is highly animistic and centers on a bear cult; a captive bear is sacrificed at an annual winter feast and his spirit, thus released, is believed to guard the Ainu settlements.