IAO may mean several things:* The Information Awareness Office, a branch of the U.S. Defense Advanced Research Projects Agency. The International Astronomy Olympiad, an internationally recongnized annual astronomy competition for high-school students. The Indian Astronomical Observatory, home of the highest telescope in the world. The Incorporated Association of Organists, a UK based organisation to which Societies of Organists generally subscribe. It publishes a journal, Organists Review. I… (More on Iao)