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English definition of “OS”

OS

noun     /ˌəʊˈes/ US  /ˌoʊ-/
[U] abbreviation for the Ordnance SurveyMaps and map-makingNamed organizations and societies and their members [C] → operating systemComputer programming and software
(Definition of OS noun from the Cambridge Advanced Learner's Dictionary & Thesaurus © Cambridge University Press)
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