A dynamic-link library is a shared library in the Microsoft Windows or OS/2 operating system. A DLL can contain executable code, data, and resources.
A DLL file often has file extension .dll even though this is not required. The extension is sometimes used to describe the content of the file. For example, .ocx is a common extension for an ActiveX control and .drv for a legacy device driver.
A DLL that contains only resources can be called a resource DLL.
