Oa is a fictional planet that lies at the center of the DC Comics universe. Since its inception, Oa has been the planetary citadel of the Guardians of the Universe and the headquarters of the Green Lantern Corps.
The Oakland Raiders are a professional American football franchise based in Oakland, California.
Oakland /ˈoʊklənd/ is the largest city and the county seat of Alameda County, California, United States.
The oat (Avena sativa), sometimes called the common oat, is a species of cereal grain grown for its seed, which is known by the same name (usually in the plural, unlike other cereals and pseudocereals).
Oakville is a suburban town in southern Ontario, located in Halton Region on Lake Ontario, and is part of the Greater Toronto Area, one of the most densely-populated areas of Canada.