OAS or Oas may refer to:* Organization of American States, an international organization of the Americas Ohio Auction School, an auction school in Ohio, USA Old Age Security, a social security payment available to most 65+ Canadians Oracle Application Server, an integrated, standards-based software platform Oral allergy syndrome, an allergic reaction to certain fruits, nuts, and vegetables that develops in hay fever sufferers Organisation de l'armée secrète, a short-lived, French… (More on Oas)