MSDN里面对于HINSTANCE的解释是"handle to an instance" 就是说是一个instance的句柄。
而对instance的解释是"An object for which memory is allocated or which is persistent." 占有内存的一个对象。
对于HWND的解释是“Handle to a window.”而对window的解释是"In a graphical Windows-based application, a window is a rectangular area of the screen where the application displays output and receives input from the user. Therefore, one of the first tasks of a graphical Windows-based application is to create a window. "
就是说是屏幕上的一块区域。