c-decay

Etymology
c, the symbol used in physics for the speed of light + decay

Noun

 * 1)  The discredited theory that the speed of light has decreased over time, proposed by creationists in order to support the belief that the universe is a few thousand years old even though there are objects visible today that are billions of light years away (whereas a constant speed of light would indicate that the universe is billions of years old and so contradict this belief).