A software distribution, also referred to as a software distro, is a bundle of a specific software (or a collection of multiple, even an entire operating system), already compiled and configured. It is generally the closest thing to a turnkey form of a usually GPL or open source source code for a software. It may take the form of a Binary Distribution, an executable installer which can be downloaded from the Internet. Examples range from whole operating system distributions to server and interpreter distributions (for example WAMP installers). Software distribution can also refer to Careware and Donateware.
They can be either official distributions by the makers of the software, or 3rd party distributions. Notable is the fact that one using such 3rd party distributions will have to turn to the distribution maker for support, the developers of the actual software being distributed usually do not provide support for 3rd party distributions of their software.