U

Underwriting

Underwriting is an announcement made on Public Broadcasting outlets, in exchange for funding

UPS

An uninterruptible power supply (UPS), uninterruptible power source or sometimes called a battery backup is a device which maintains a continuous supply of electric power to connected equipment by supplying power from a separate source when utility power is not available 

User interactive elements

These are other elements which provide the opportunity for the web user to interact with the website in multiple ways. These include feedback forms, polls, surveys, etc.