What is the origin of the name Oz in the Wizard of Oz?

Answer 1

From wikipedia

http://en.wikipedia.org/wiki/Land_of_Oz#cite_ref-autogenerated8_63-1

A legend of uncertain validity is that when relating bedtime stories (the earliest form of the Oz books) Baum was asked by one of his listeners the name of the magical land. He glanced at a nearby filing cabinet, which had three drawers, labeled A-G, H-N, and O-Z. Thus he named the land Oz. This story was first told in 1903, but his wife always insisted that the part about the filing cabinet was not true.[64] In Dorothy and the Wizard in Oz, the name is translated as "great and good", which is roughly equivalent to the meaning of "Öz" in Turkish, although that would be pronounced more like "ohs," which Jack Snow suggested was a possible pronunciation of the name.

Another theory is that Oz is a corruption of Uz (interestingly, that's the word used to translate Oz to modern Hebrew), the homeland of Job in the Old Testament.[64] It is also speculated that Oz was named after the abbreviation for ounce, in the theory that Oz is an allegory for the populist struggle against the illusion (the wizard) of the gold standard. "Os" (with an s) is also Old English for God.

Several of Baum's fairy stories that take place in the United States were situated on the Ozark Plateau, and the similarity of name may not be a coincidence.[65]

In Wicked, Elphaba researches the etymology of Ozand concludes that it comes from either oasis, because it is surrounded by desert on all sides, or ooze, due to the creation legend of a great flood.

Oz is a common vernacular contraction of Australia(Australia-Aussie-Aus-Oz). Australia is a large continent predominated by desert regions, with pockets of intense green tropical, sub-tropical and sub-alpine greenlands and rainforests. It is quite possible that Baum took the popular nickname of Australia as the national name for his fictional world. Also note that many fans place Oz in the South Pacific, see Location above. However, according to the Oxford English dictionary, the first references to Australia by this name were made in 1902-after the first book had been published.

Others have said that Oz stands for New York, since the letters before O and Z respectively are NY.

In the Sci-fi mini-series "Tin Man" Oz was portrayed as an acronym for The Outer Zone.