Orsa or ORSA may refer to: Places: Orsha or Orša, Belarus Orsa, Sweden Orsa Municipality, Swedish municipality Vessels: Orsa-class torpedo boat, built for the Italian Navy in the 1930s Italian training ship Orsa Maggiore (A5323), a contemporary ocean ketch serving as a sail training vessel Other uses: Orsa (moth), a moth in the family Erebidae Operations Research Society of America Own Risk and Solvency Assessment, in EU insurance regulation Oxacillin-resistant Staphylococcus aureus