The Akimel O'oham or Pima are a group of American Indians living in an area consisting of what is now central and southern Arizona (USA) and Sonora (Mexico). The name means "river people". They are closely related to the Tohono O'odham (meaning "desert people", formerly known as Papago), the Hia C-ed O'odham, and the Sobaipuri, a now extinct group. The name "Pima" apparently comes from a phrase that means "I don't know", used repeatedly in their initial meeting with Europeans.