How to open .def file format?

The probably reason why you are at this website is a problem with opening .def file. The full name of the file is M.U.G.E.N. Character Definition File. If the double-click on the file’s icon shows you a message that additional programs are needed to open the file, you’ll find the list of helpful programs in the bottom of the page.The developer of this format is Elecbyte.

.def file extension (M.U.G.E.N. Character Definition File)

Category Developer/Producer File description Popularity
Game Files Elecbyte M.U.G.E.N. Character Definition File
Rate
Programs using this file extension: .def