1. Naut. See able seaman.2. airborne.3. U.S. Air Force. Airman Basic.4. Alberta, Canada (approved for postal use).5. antiballistic; antiballistic missile.a major blood group usually enabling a person whose blood is of this type to donate blood to persons of type AB and to receive blood from persons of type O, A, B, or AB. Cf. ABO system.
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