When searching for health care resources or organizations for Indigenous peoples, there are a wide range of terms that have been used historically to refer to the community. Some terms work better than others, so please be aware:
American Indian - a member of any of the indigenous peoples of the western hemisphere except often those distinguished as Inuit. Particularly refers to an American Indian of North America and especially the U.S. (Merriam-Webster).
Indian - relating to or denoting indigenous peoples of North, Central, and South America, especially those of North America. (Merriam-Webster). It is a controversial, antiquated term, and is highly discouraged for use by anyone who is non-Indigenous, although some older Indigenous people may still prefer the term to self-identify. The term is also wrapped up in U.S. government recognition of Indigenous status, which may be connected to one's eligibility to live on a reservation or apply for social services and aid directed towards recognized Indigenous peoples. More often one will see "American Indian" to avoid confusion with people who originate from the country of India.
A note on calling Indigenous people Indian/American Indian, from the perspective of an Indigenous person:
"This one is tricky. After 600 years of being incorrect, our primarily white government has made "American Indian" an official term for Natives. In fact, the official federal agency that oversees Native land management is called the Bureau of Indian Affairs, however I know a lot of Natives that don't like being called Indian because that just isn't who we are — we're not from India. A good rule of thumb for this is when referring to Natives, call us Native American, Indigenous, First Nations, or preferably by our specific band or tribe, and just let Natives call each other Indian." (Insider, "7 things you should never say to a Native American")
Native American - a member of any of the indigenous peoples of the western hemisphere; especially a Native American of North America and especially the U.S. (Merriam-Webster). The term Native American also began to emerge during the 1960s. It's since been widely used by those who prefer to eliminate the "Indian" pejorative entirely (Seeker).
Native - shorthand for Native American. Often used to replace "Indian" as an adjective for anything or anyone belonging to Indigenous peoples or culture. Similar to "Indian," while it is preferred, the term "Native" may still carry a negative connotation or might seem outdated (Indigenous Foundations). It is overall better to say broadly "Indigenous" or to refer to a person by their tribe name/nationality, a.k.a. "Cherokee" or "Inuit."
First Nations - “First Nation” is a term used to describe Aboriginal peoples of Canada who are ethnically neither Métis nor Inuit. This term came into common usage in the 1970s and ‘80s and generally replaced the term “Indian,” although unlike “Indian,” the term “First Nation” does not have a legal definition (Indigenous Foundations).
Aboriginal - being the first or earliest known of its kind present in a region; of or relating to the indigenous peoples of Australia (Merriam-Webster). In Australia, "Aboriginal" is okay to refer to an indigenous person or peoples, but "Indigenous" would be best. Rather than refer to someone as Aboriginal, try using the person’s clan or tribe name. And if you are talking about both Aboriginal and Torres Strait Islander people, it’s best to say either 'Indigenous Australians' or 'Indigenous people' (Amnesty International)
Inuit - Inuktitut for “the people” — are an Indigenous people, the majority of whom inhabit the northern regions of Canada. (The Canadian Encyclopedia). Canada's 1982 Constitution Act recognized the Inuit as Aboriginal peoples in Canada, but not First Nations.They have a different agreement with Canada which is based more on land agreements, not signed treaties (Government of Canada).
Tribe - is used in many different contexts to refer to a category of human social group (Wikipedia, "Tribe"). There are 561 federally recognized tribal governments in the United States, which are recognized as having the right to establish their own legal requirements for membership. In recent times, legislation related to Indians uses the "political" definition of identifying as Indians those who are members of federally recognized tribes. Most often given is the two-part definition: an "Indian" is someone who is a member of an Indian tribe and an "Indian tribe" is any tribe, band, nation, or organized Indian community recognized by the United States (Wikipedia, "Native American Identity in the United States").
Reservation - An Indian reservation is a legal designation for an area of land managed by a federally recognized Indian tribe under the U.S. Bureau of Indian Affairs rather than the state governments of the United States in which they are physically located. In Canada they are legally referred to as "Indian reserves," which are specified by the Indian Act as "tracts of land, the legal title to which is vested in Her Majesty, that have been set apart by Her Majesty for the use and benefit of a band." (Wikipedia, "Indian reservation").
"Terminology can be critical for Indigenous populations, as the term for a group may not have been selected by the population themselves but instead imposed on them by colonizers. With this in mind, one might understand how a term can be a loaded word, used as a powerful method to divide peoples, misrepresent them, and control their identity. On the other hand, terms can empower populations when the people have the power to self-identify. It is important to recognize the potential these words may hold— but it is also important and very possible to understand these terms well enough to feel confident in using them and creating dialogue." (Indigenous Foundations)