The term Nez Perces (French for "pierced noses") is a derogatory term for several Native American groups (which some have come to accept).
The first group referred to as Nez Perces were the Ioway, a French derivation of the Dakota word for them (Ayuhwa or "sleepy ones"). They called themselves the Pahodja though ("dusty noses"), although the fur traders called them Nez Perces. The Algonquins knew them as the Nadouessioux Maskoutens or the Dakota of the Prairies.
Further West in Idaho were the Nimiipu ("the people"), a semi-nomadic group also called the Nez Perces for their nose pendants. This tribe still exists on a reservation in Lapwai, Idaho and they even have a tribal website at www.nezperce.org with history, their tribal code, and so on; although they have removed all reference to the source of the name "nez perces."