postseasonPronunciation: /ˈpəʊstsiːz(ə)n/Definition of postseason adjective chiefly North American (of a sporting fixture or other event) taking place after the end of the regular season: a postseason game noun the period following the regular season: he was sidelined until the postseason a game or competition held during the postseason: his team qualified for the postseasonpostseason in other Oxford dictionaries Definition of postseason in the US English dictionary