Spelled "Vasuix" lake on Trutch maps 1866 and 1871; a mis-spelling of the French word vaseux, meaning muddy or mirky - descriptive of the lake's silty water. Probably named by French Canadian fur traders. For many years the name was spelt Vaseaux; in 1945 the Geographic Board corrected it to Vaseux at the suggestion of H J Parham, Penticton. (12th Report of the Okanagan Historical Society, 1948).
Source: BC place name cards, or correspondence to/from BC's Chief Geographer or BC Geographical Names Office