UI stands for User Interface and refers to the visual design and layout of a website or application. It includes elements such as buttons, menus, and text.

UX stands for User Experience and refers to how easy or satisfying it is to use a website or application. It includes aspects such as ease of navigation, overall flow and functionality, and how well it meets the user's needs.

In simple words, UI is how the website or application looks and feels, while UX is how the user interacts with it and how well it meets their needs.