UHF  – Ultra High Frequency (TV channels 14-74)

URL – Uniform resource location, also known as Internet address

USP – Abbreviation for unique selling proposition. The unique benefits that a companies products or services offer customers.

Unilluminated or Non-illuminated Panel – Name given to a standard poster panel not equipped with illumination.

Unique Visitors – A term used to describe the total number of visitors to a site over a certain time period. The only way to accurately track this is to require each visitor to login with a unique user name to gain access to a site. Relying exclusively on IP addresses in a log file is not recommended as it would not take into consideration multiple users accessing ones site through the same IP address such as would happen at companies and schools. Cookies are also used sometimes, but since they can be disabled or cached, they cannot be relied upon exclusively.

Unix – A multi-user computer operating system (OS) with support for TCP/IP, Unix is available in many varieties and is the most popular OS for Internet web servers. Another popular OS is Linux, which is based on Unix.

Upscale – A demographic determination meaning affluent, better educated, professionals.

Up Sell – The process of making an additional offer for related products/services to a customer after they have committed to a sale but before they have completed the transaction.