Software distribution
A software distribution is a installer of a specific software (or a collection of multiple, even a 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 usually takes the form of a either rpm, deb, tgz, msi, exe etc. installer and is downloadable from the internet .
Examples range from whole operating system distributions (distro's) to server and interpreter distributions eg: WAMPP installers
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.