.UDF File Extension

File created in the Universal Disk Format (UDF), a disc imaging format used for storing files on optical media; stores a collection of files using the directory structure specified in the UDF standard; can be used for burning DVDs, CDs, and other optical media; allows files to be deleted and modified on the target disc even after they have been written.

The UDF standard is developed and maintained by the Optical Storage Technology Association (OSTA).

NOTE: Even though the UDF format is commonly used, the ".udf" extension is not. Instead, disc burning applications typically save images in their own formats and then burn them using the UDF standard.

User-defined script written or recorded in Visual Basic that executes a function in Microsoft Excel; can be created by selecting "Module" from the Insert menu in Excel.