.UDC File Extension
File TypeAdobe InDesign User Dictionary
What is a UDC file?
File used by InDesign, a desktop publishing and page design application; contains a word list used by the software's spell checker; can store exceptions and user-defined words, as well as words from a dictionary.
InDesign dictionaries can be accessed by selectingin Windows or in Mac OS X. UDC files are often used to share custom dictionaries between multiple users in a company.