Prefix. Bi-, a number prefix denoting two, as in: Air Sylphe Bi 582, a two-seat French powered parachute design; Bisexuality, or "bi", a sexual orientation of more than one biological sex; Places. Barrie—Innisfil, a Canadian electoral district; Burundi, by World Meteorological Organization and ISO 3166-1 country code; People. Bi (Rain), or Rain (born 1982), South Korean singer