Uptime and downtime describes how long a website, computer, or other system has been working (uptime) or not working (downtime).

User Experience describes the emotions, attitudes and ease of use a person has when using a product or service.  UX Design is the use of design to improve communication between a product and its user to enhance the user’s overall experience. It is not simply about how something looks. In the context of transport, a good …

User interface includes all the parts of a website, app, computer, smartphone, etc. that the user can manipulate and interact with. Display and touch screens, website menus, keyboards, your cursor—these are all part of a user interface.

A URL (colloquially termed a web address) is a reference to a web resource that specifies its location on a computer network and a mechanism for retrieving it.