The seven Principles of Universal Design are often quoted and used in both academic and practical publications.
The 8 Goals of Universal Design build on the 7 Principles to make them more practical.
Universal Design is about accepting and celebrating diversity. So there are many ways to explain universal design.
This short video about universal design is powerful in its simplicity. One of the best explanations around. Great for introducing the idea of inclusion and universal design to newcomers. A good example of a universally designed video and universally designed explanation as well.