VSO's a three-letter acronym with multiple meanings, as described below:* Scout observation plane in the United States Navy Valdosta Southern Railroad Vancouver Symphony Orchestra Variable Speed Oscillator Verb Subject Object in Linguistic typology Vermont Symphony Orchestra Victoria State Opera, Australian opera company, merged in 1996 with Opera Australia Vienna State Opera Vienna Symphony Orchestra Voluntary Service Overseas, an international development charity Volvo Super Olympian… (More on Vso)