User experience (abbreviated UX) is a term that describes how good and pleasant it is for you as a user to use a website, app or other digital product.
Imagine downloading two different apps that basically do the same thing — weather apps, for example. One app is completely confusing, you can't even find your way around and after 5 minutes you don't feel like it anymore.
With the other app, everything is self-explanatory. You can immediately find the most important functions and check the weather for your location. The app is fun to use and you don't even notice how time flies.
The first app has a poor user experience (UX), the second a good one. UX therefore describes how satisfied and happy an app, website or other digital product makes you as a user.
But UX goes even further: It also describes how easy it is to operate “analog” products such as a remote control or a car. Everything you use in your everyday life has a user experience. The job of UX designers is to make this user experience as pleasant as possible. Because the better the UX, the more you'll want to use a product and more often.