Uncharitably listed in the Wabaningo Lodge Emblem Handbook (1952) as "Minor chief of the Walla Walla tribe," the name Walamootkin was adopted from the band of Cuupn’itpel’uu (Chute-pa-lu; meaning "people walking out of the mountains into the plains.") who lived in the Wallowa Valley and were led by the renowned Chiefs Tuekakas (or Tiwi-teqis; also known as Old Chief Joseph) and his son Hinmatóowyalahtq̓it (also seen as Hin-mah-too-yah-lat-kekt and In-mut-too-yah-lat-lat; also known as Chief Joseph or Joseph the Younger). At that time, the Chute-pa-lu people were organized into local bands which were not tightly associated through regional social or political structures (like the modern Nez Perce nation). The band that lived in the Wallowa Valley referred to themselves as the Wal-lum-wat-kain or Wellamotkin Band. [In Chief Joseph’s speech at Lincoln Hall in Washington D.C. in 1879 (published in North American Review, Vol. 128, Issue 269, pp. 412-434), he refers to himself as a member of the 'Wal-lum-wat-kin Band' of Chute-pa-lu.] This name might be derived from the Chute-pa-lu word "iwetemlaykin", which means "at the edge of the lake" (i.e., perhaps they were referring to themselves as the people who lived at the edge of the lake).
The name Hinmatóowyalahtq̓it translates to "thunder rolling down the mountain". This meaning has been mis-attributed to the Walamootkin name.