Ozark, Overhill, Ottawa, Oleander, Oriole, Olmsted, Onarga, Oliphant, and so on. Just about every north-south and diagonal street in Edison Park begins with an "O," which came about in 1910 when the neighborhood was annexed into Chicago. Many of the newly annexed areas had streets that shared names with existing Chicago streets, so to solve this, the "new" streets on the north side of the city were renamed in mile-wide swatches of alphabetic letters. Doing so eliminated duplicate names and helped the post office sort mail. Edison Park, which is named for inventor Thomas Edison, inherited "O," and had many of it's streets named for Native American tribes (several of these were later "renamed to more manageable, spellable" words).