DEF extension files can take various application formats, some of them
In this first case, the DEF file is a game data file used by M.U.G.E.N.,
a sprite-based game engine used to make 2D fighting games.
More about M.U.G.E.N.
It is a freeware 2D fighting game engine designed by Elecbyte.
Content is created by the community, and thousands of characters, both
original and from popular fiction, have been created.
It was programmed in C through the Allegro library.
The latest versions of the engine use the SDL library.
The DEF file contains the definition of a character, that’s where the
acronym comes from, including the character’s name and version information
and the character specification files used by the engine.
In this case, the DEF file is a database and spreadsheet format used by
the SmartWare II database software.
More about Smartware II
SmartWare II allows users to create or modify a switching strategy and
send it to a control.
It also allows you to read the current configuration, save or load a
configuration to or from a file, monitor control operation in real time,
and retrieve historical data.
IOBit Malware Fighter
In the latter case, the DEF file is a file used by IObit Malware Fighter,
a program used to remove malware and spyware from the PC.
IObit Malware Fighter is one of the most widely used antivirus packages
worldwide, however, it has received negative reviews on certain occasions.
The DEF file stores virus definitions used to identify and remove malware
from your computer.
DEF files use the file names core000.def, core001.def, core002.def, etc.
They are stored in the db\ directory of the IObit Malware Fighter
In this case, the DEF file lists the exports and attributes of a program
to be linked by an application linker.
The DEF is 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.
More about Visual Studio
This is Microsoft’s flagship integrated development environment.
It is used to develop any type of software, due to the large number of
languages and scripts it handles.
Among his development examples are computer programs, websites, web apps,
web services and mobile apps.