The process of putting your design or product in front of real users to see how well it holds up in the wild. It’s like a dress rehearsal for your app, where you find out if people can actually navigate it, complete tasks, and (hopefully) enjoy the experience. Usability testing reveals where things get clunky, confusing, or downright frustrating, so you can make tweaks before launch. It’s all about catching those “Oops!” moments early, so users don’t have to suffer through them later.