Atsina

Gros Ventre
Haaninin

Assiniboin Boy, a Gros Ventre man, photo by Edward S. Curtis
Total population
(3,682 (2000 census))
Regions with significant populations
United States ( Montana)
Languages
English, Gros Ventre
Religion
Roman Catholicism, Sun Dance, traditional religion
Related ethnic groups
Arapaho, Cheyenne

The Gros Ventre (English pronunciation: /ˈɡroʊvɑːnt/; from French: "big belly"), also known as the A'ani, A'aninin, Haaninin, and Atsina, are a historically Algonquian-speaking Native American tribe located in north central Montana. Today the Gros Ventre people are enrolled in the Fort Belknap Indian Community of the Fort Belknap Reservation of Montana, a federally recognized tribe with 3,682 enrolled members, that also includes Assiniboine people or Nakoda people, the Gros Ventre's historical enemies. The Fort Belknap Indian Reservation is in the northernmost part of Montana, just south of the small town of Harlem, Montana.

A'ani, A'aninin, and Haaninin are the tribe's autonyms. These terms mean "White Clay People" or "Lime People".

The French used the term Gros Ventre, which was mistakenly interpreted from their sign language. They were once known as the Gros Ventres of the Prairies, while the Hidatsa people were once called the Gros Ventres of the Missouri.

The Piegan Blackfoot, enemies of the Gros Ventre throughout most of history, called the A'aninin, "Piik-siik-sii-naa", which translates as "snakes". According to the Piegan Institute, the contemporary Piegan name for the Gros Ventre is "Assinee", meaning "big bellies", which is similar to the falsely translated label applied by the French. Atsina, a Pieagan word, translates to either "gut people" or "like a Cree". Further clarification of the name is required. After the division of peoples, their relations the Arapaho, who considered them inferior, called them Hitúnĕna, meaning "beggars". Other interpretations of the term have been "hunger", "waterfall", and "big bellies".