What is the definition of March Madness betting? The term March Madness really refers to the NCAA men’s basketball Tournament that is played each March. That is how most people would define March Madness betting. What is the definition of March Madness betting could also include the many college basketball conference tournaments and the NIT. There is no doubt that many people consider the conference tournaments and the NIT as part of March Madness betting. What is the definition of March Madness betting can refer specifically to the March Madness brackets but betting is so much a part of the tournament that people include it when asking the what is the definition of March Madness betting question.