Short answers, pulled from the story.
There is no generally accepted definition of Indigenous peoples in the United Nations or international law. In the 21st century the focus has been on self-identification, cultural difference from other groups in a state, a special relationship with traditional territory, and an experience of subjugation and discrimination under a dominant cultural model.
Estimates of the population of Indigenous peoples range from 250 million to 600 million, with some counts reaching as high as a billion. They comprise some 5,000 distinct peoples spread across every inhabited climate zone and inhabited continent.
Indigenous derives from the Latin word indigena, meaning sprung from the land, native. The Latin indigena combines the Old Latin indu, meaning in or within, with gignere, meaning to beget or produce.
Sir Thomas Browne first used the term in 1646, writing that Africans serving under the Spaniard were transported from Africa and were not indigenous or proper natives of America. Europeans used it to differentiate the Indigenous peoples of the Americas from enslaved Africans.
The 1989 International Labour Organization Convention on Indigenous and Tribal Peoples, known as Convention No. 169, protects Indigenous peoples from discrimination and specifies rights to lands, resources, employment, education, and health. In 2007 the United Nations adopted the Declaration on the Rights of Indigenous Peoples, endorsed by at least 148 states, affirming the right to self-determination.
Several governments reject the label or apply restrictive criteria. Bangladesh has stated there are no Indigenous peoples in the country, Indonesia denies the concept applies within its borders despite a local group classifying 50 to 70 million people as Indigenous, and Russia recognizes only 40 ethnic groups, excluding peoples numbering more than 50,000 such as the Sakha and Komi.
In 1492 the population of the Americas was about 50 to 100 million, but by 1700 introduced diseases had reduced the native population by 90 percent. By 1800, North America held about 5 million Europeans and their descendants, one million Africans, and 600,000 Indigenous Americans.