SO2 may refer to: In science: Sulfur dioxide (SO2), an oxide of sulfur, a chemical compound to a Sulfonyl group (R-SO2-R) The special orthogonal group of degree 2 oxygen saturation (SO2), in medicine of blood oxygenation S2 (star), aka SO-2, is the name of a star near the central black hole at the center of the Milky Way galaxy that takes 16 years to orbit that black hole. 2015 SO2, an Aten asteroid in a horseshoe orbit co-orbital with Earth It may also refer to: A staff officer of the second class, often a commissioned officer of lieutenant commander, major or squadron leader rank A London Metropolitan Police Specialist Operations command division Special Operations 2 – Operational, of SOE (Special Operations Executive, British, World War II) Star Ocean 2, a video game SO2 (album), a 2010 album by Shinichi Osawa An abbreviation of "Shout-out to" See also Soso (disambiguation) Soo (disambiguation) SO (disambiguation)