The conception inside computational complexness theory. Look at Big O notation. The Japanese anime series. View The Big O. The euphemism for orgasm. A 1976 Summer Olympic Stadium in Montreal. Oscar Robertson, a basketball player. Big O Tires, a tyre company in the United States. The Big O, a Roy Orbison album, or Roy Orbison himself. The Missing Piece Meets the Big O, a toddlers's book by Shel Silverstein