Klamath
noun/ˈklæməθ/
Etymology From Chinook Jargon Tlamatl (“either "swiftness" or "they of the river"”), with the first syllable's onset consonant cluster dissimilated and the coda of the second syllable changed to the somewhat similar-sounding interdental fricative during the process of anglicization.
1
Any member of a Native American tribe formerly living along the Klamath River in California and Oregon.