Several plausible but nevertheless quite unsatisfactory etymologic interpretations of the name, Assiniboin, have been made by a number of writers. Among these interpretations are “Stone Roasters,” “Stone Warriors,” “Stone Eaters,” etc. These are unfortunately historically improbable. It appears that difficulty arises from a misconception of the real meaning of the limited or qualified noun it contains, namely, _boin_. This element appears in literature, dialectically varied, as _pour_, _pouar_, _poil_, _poual_, _bwân_, _pwan_, _pwât_, etc. Evidently, it was the name of a group of people, well known to the Cree and the Chippewa tribes, whom they held in contempt and so applied this noun, _boin_, _bwân_, _pwât_, etc., to them. The signification of its root _bwâ_(n) or _pwâ_(t) is “to be powerless, incapable, weak.” So that _Pwâtak_ or _Bwânŭg_ (animate plurals) is a term of contempt or derision, meaning “The Weaklings, The Incapable Ones.” This name was in large measure restricted to the nomadic group of Siouan tribes in contradistinction from the sedentary or eastern group of Siouan peoples who were called Nadowesiwŭg, a term appearing in literature in many variant spellings. The name Dakota in its restricted use is the appellation of the group of tribes to which the name _Bwânŭg_, etc., was applied. This fact indicates that the _Assiniboin_, or _Assinibwânŭg_, were recognized as a kind of Dakota or Nakota peoples. Nakota is their own name for themselves. The rupture of the Dakota tribal hegemony thrust some of these peoples northward to the rocky regions about Lake Winnipeg and the Saskatchewan and Assiniboin rivers. So it was these who were called Rock or Stone Dakota (i. e., _Bwânŭg_). It would thus appear that the rupture occurred after there were recognized the two groups of Siouan tribes in the past, namely, the nomadic or western, the Dakota, and the sedentary or eastern, the _Nadowesiwŭg_ of literature. Traditionally, the Assiniboin people are an offshoot of the Wazikute gens of the Yanktonai (Ihañkto^nwa^nna) Dakota. Dr. F. V. Hayden in his “Contributions to the Ethnography and Philology of the Indian Tribes of the Missouri Valley” says that Mr. Denig was “an intelligent trader, who resided for many years at the junction of the Yellowstone and Missouri Rivers as superintendent of Fort Union, the trading post for the Assiniboins.” Of the vocabulary of the Assiniboin language, recorded by Mr. Denig, Doctor Hayden wrote that it is “the most important” one theretofore collected. From the citation from Mr. Denig’s description of Fort Union in a preceding paragraph it appears that Doctor Hayden is in error in making Mr. Denig superintendent of the fort rather than of the office of the American Fur Co. at that point. In one of his letters Reverend Father Terwecoren wrote that Mr. Denig, of the St. Louis Fur Co., is “a man of tried probity and veracity.”