In C programming language, an assembly refers to a compiled code that can be executed by the Common Language Runtime (CLR) . An assembly is the smallest unit of deployment for any .NET project, and it typically contains .NET code in Microsoft Intermediate Language (MSIL) that will be compiled to native code the first time it is executed on a given machine. Assemblies can take the form of executable (.exe) or dynamic link library (.dll) files, and they are the building blocks of .NET applications.

It is important to note that the term "assembly" can also refer to assembly language, which is a low-level programming language that is used to write programs that interact directly with the hardware of a computer. However, this is not the same as the assembly in C# or .NET.