OOS (Out Of Stock) indicates an item is no longer available—sold out at retail or depleted from a seller's inventory. The abbreviation appears in release discussions ('went OOS in 2 minutes'), seller updates ('size M now OOS'), and general availability conversations. OOS status triggers the shift from retail to resale market—once something is OOS at retail, secondary market becomes the only option. Quick OOS times indicate high demand and often predict strong resale values. Tracking OOS timing helps understand hype levels and brand demand patterns. For highly anticipated releases, OOS can happen in seconds as bots and prepared buyers deplete inventory instantly. The abbreviation efficiently communicates availability status in fast-moving discussions where brevity matters.