DEF File Type

- The quick facts

What are DEF files and how to open them

Are you having problems opening a DEF file or just wondering what they contain? We explain what these files are used for and show you software that we know can open or otherwise handle your files.

What is a DEF file?

Files that contain the .def file extension are most commonly associated with Microsoft Visual C++ definition files. These files list the exports and attributes of a specific program that is linked by an application linker.

The DEF file format is commonly used when creating a dynamic link library during the development of a software application.

The 3D Fassade Plus software application also uses the .def file extension. These DEF files contain definition module files that are used by the software.

A variety of Nova Logic software games also use files with the .def file suffix. These DEF files contain game weapon files that are referenced by the software during a user's gameplay.

How to open DEF files

Important: Different programs may use files with the DEF file extension for different purposes, so unless you are sure which format your DEF file is, you may need to try a few different programs.

While we have not verified the apps ourselves yet, our users have suggested 10 different DEF openers which you will find listed below.

Last updated: April 4, 2022

Suggest another file format using extension DEF

While we know of one file format using the .DEF file extension, there may be more. It is widespread that different programs use files with the same file extension for very different types of data. Please let us know if you are aware of a different kind of .DEF file.

Various apps that use files with this extension

These apps are known to open certain types of DEF files. Remember, different programs may use DEF files for different purposes, so you may need to try out a few of them to be able to open your specific file.

Army BuilderArmy BuilderUser submitted
progeCAD ProfessionalprogeCAD ProfessionalUser submitted
Movie Magic ScreenwriterMovie Magic ScreenwriterUser submitted
WinEdtWinEdtUser submitted
MapBasicMapBasicUser submitted
TimetableTimetableUser submitted
Open WatcomOpen WatcomUser submitted
Evaluation FlashEvaluation FlashUser submitted
IrfanViewIrfanViewUser submitted
SingularLogic Report ViewerSingularLogic Report ViewerUser submitted