U

UDP

User Datagram Protocol; a protocol defining a connectionless, unreliable transport-layer service between applications on the Internet.

unsettled transactions

All transactions must be settled before any money changes hands. Please note that authorization transactions are not captured until they are completed by a delayed capture transaction.

upload

The sending of files from your local hard drive to another computer over a network.

URL

Uniform Resource Locator; a protocol for defining the exact location of a World Wide Web resource, and for identifying the method of access, the host on which it resides, and the path and filename of the resource.