postseason adjective 1noun 1forms 1 adjective1 •(US) Of or pertaining to such a period. noun1 •(US) The period after the end of the normal sports season during which extra games are held (such as playoffs or championships).Suárez has only two more starts in the regular season to convince the Phillies he deserves a longer leash than in previous postseasons. — 2024 formspostseasons