So here's the irony wrapped in irony. The Gold Rush inspired the U.S. government to drive Indians off their land. Manifest destiny and all that, dontcha know. An army battalion chased a group of Indians into the Yosemite Valley in 1851, whereupon they "discovered" the beauties of the valley. The company physician, Dr. Lafayette Bunnell was most awestruck with the scenery and decided to name the valley after the tribe they were intent upon dispossessing. He thought the the tribe's name was Yosemite, and thus the name of the valley came about.
Later he "discovered" that the tribe actually called themselves the Ahwahneechees, and the word yosemite was part of the Miwok language (yohhe'meti).
And the meaning of the word?
They are killers.
If you wrote that in a story, people would not believe it.