BYY or Byy can refer to: ISO 639:byy or "Buya", a spurious ISO 639 code that may refer to Buyu language, spoken in the Democratic Republic of the Congo Bay City Municipal Airport, an airport in Bay City, Texas, U.S., by FAA LID code Bayleyite, a yellow, uranium-containing mineral, by International Mineralogical Association symbol Byree railway station, a train station in Odisha state, India Biyang County, an administrative division of Zhumadian, Henan, China; see List of administrative divisions of Henan