The Steam Deck is a handheld gaming device developed by Valve Corporation, designed to play PC games on the go. It runs a custom Linux-based operating system called SteamOS, allowing users to access and play their Steam library as well as install other software. The device features a touchscreen, physical controls, and powerful hardware, making it capable of running modern PC games. Its open platform also enables users to install third-party applications and even other operating systems, offering flexibility beyond traditional gaming consoles.