His Hocąk name is given as WaConChaChoNeeKah, which is for Wakąjáčonįga, "First Thunderbird", a personal name in the Thunderbird Clan. It is from Wakąjá, "Thunderbird"; čonį, "first, new"; and -ga-, a definite article suffix used in personal names.
William was born in 1873. In numerous censuses, he explicitly uses the suffix "Sr." and on the previous page, his son is found using the suffix "Jr." (cf. 1911 census) He was a young teenager when he fathered his oldest son, William Jr., being only 16 years old. His wife Carrie was 5 years younger (b. 1878), and could hardly have been 11 years old when giving birth, so we must conclude that William Sr. had first been married to another woman.
Indian Census Rolls, 1885-1940; (National Archives Microfilm Publication M595, 692 rolls); Records of the Bureau of Indian Affairs, Record Group 75; National Archives, Washington, D.C. ⬆︎1911; Roll: M595_570; Line: 5; Agency: Tomah Indian Ind'l School.