Chaitin's Constant is a number that was invented by mathematician Gregory Chaitin in the 1970s. It is a way of describing the amount of randomness in mathematics. Basically, it's like a number that measures how hard math is to understand and predict. To understand it better, think of it like a number that tells you how likely something is to be random. The higher the number, the higher the chance that the math is random and unpredictable.