The Xbox One is Microsoft's eighth-generation gaming console, released in 2013. The "One" in its name represents Microsoft's vision of a unified entertainment system—the company wanted a single device to serve as the "one" console for all gaming and media needs in the living room.
There is no separate numeric designation beyond "Xbox One." Microsoft's Xbox console generations follow this naming pattern: the original Xbox (2001), Xbox 360 (2005), and Xbox One (2013). When Microsoft released newer versions, they used variant names rather than sequential numbers—the Xbox One S, Xbox One X, and later the Xbox Series X and Xbox Series S (ninth generation, released 2020).
If you're asking about a specific model number or product code for a particular Xbox One variant, those are typically found on the console's packaging or in the system settings under "System Info," displayed as alphanumeric codes rather than simple numbers.