PSO may refer to:
Orchestras Pacific Symphony Orchestra Peoria Symphony Orchestra Pittsburgh Symphony Orchestra Plano Symphony Orchestra Portland Symphony Orchestra Perth Symphony Orchestra
Science and technology Particle swarm optimization, a swarm intelligence optimization technique Password Settings Object, used in Windows Active Directory environments Phase-shift oscillator, an electronic circuit that generates sine waves Projective special orthogonal group Protocol Support Organization, one of the three initial components of ICANN, later disbanded PSO J318.5-22, a rogue planet discovered in 2013 Proximal subungual onychomycosis, a type of nail infection.
Other uses Pakistan State Oil Patient safety organization Paysite operator, the operator of a paysite, typically pornographic Peace Support Operations, a military term used by NATO Penalty shootout, a method of determining a winner in sports matches which would have otherwise been drawn or tied Phantasy Star Online, a series of online role-playing video games Phantasy Star Online, the first game in the series Phone sex operator, a person who provides phone sex service Producers Sales Organization, an independent motion picture production and distribution company Protective services officer, a member of police in Australia who performs policing duties at specific locations Psoriasis, an autoimmune disease PSO-1, a Soviet telescopic sight Public Safety Officer, another name for police, firefighters, ambulance crews and other providing safety services in the U.S. Public Service Company of Oklahoma Public service obligation, a form of state subsidy for transport links which are not commercially viable Puro Sangue Orientale, a breed of horse in Italy The FAA LID code for Stevens Field airport in Archuleta County, Colorado, United States The IATA code for Antonio Nariño Airport, serving the Colombian city of Pasto Personal Security Officers Provider Services Operations, a team at the National Marrow Donor Program