Assembly file created by Pro/ENGINEER, a program used for designing three-dimensional products; contains one or more design parts (.PRT files) and their assembly specifications; used to combine parts together into an assembled component.

Assembly file created by Solid Edge, a CAD program used to create product designs; contains an assembly design, which may include one or more parts; used to store design data for simulating manufacturing assembly processes.

Assembly source code file created by Microsoft Visual Studio, a Windows software development program; contains low-level source code that can be translated directly into machine code; typically used only for optimizing small segments of application code.

Since assembly code is typically more difficult to write than C or C++ code, ASM files are often combined with C or C++ files that handle the majority of the application logic.