Although some biographers believe the story of Oz’s naming to be as fanciful as the tales themselves, author L. Frank Baum claimed that he was inspired by a file cabinet marked O–Z.
Other suggested derivations include:
a variation on Uz, Job’s house;
a variation of children’s oh’s and ah’s;
and a variation of Boz, the pseudonym for Charles Dickens, one of Baum’s favorite authors.