.DEF File Extension
File Type 1Module-Definition File
What is a DEF file?
Lists the exports and attributes of a program to be linked by an application linker; used in software development when creating a DLL.
DEF files are used by Microsoft Visual C++, a component of Microsoft Visual Studio, as well as other C++ development software.
File Type 2M.U.G.E.N. Character Definition File
.DEF File Association 2
Game data file used by M.U.G.E.N., a sprite-based game engine used for making 2D fighting games; contains the definition for a character, including the character name and version information and the character specification files (.CNS, .SFF, .CMD, and .AIR) used by the engine.
File Type 3SmartWare II Data File
.DEF File Association 3
Spreadsheet and database format used by SmartWare II database software.
File Type 4IOBit Malware Fighter Definitions File
.DEF File Association 4
File used by IObit Malware Fighter, a program used for removing malware and spyware from the PC; saves virus definitions used for identifying and removing malware from the computer.
DEF files use the filenames core000.def, core001.def, core002.def, etc. They are stored in the \db\ directory of the IObit Malware Fighter installation.