Dynamic-link library (DLL) is a module that contains functions and data that can be used by another module (application or DLL). The term is usally applied to native DLL, the .NET DLLs are usually referred just as 'library' and are vary different in nature and usage.
I am interested in using utilising third-party libraries in Unity Free. I know Unity can use managed libraries as Assets, but only the Pro version supports using native libraries. (DllImport within ...