Scrum is a "lean" approach to software development. The term Scrum comes from a 1986 study  by Takeuchi and Nonaka that was published in the Harvard Business Review. In that study, Takeuchi and Nonaka note that projects using small, cross-functional teams historically produce the best results. They write that these high-performing teams were like the Scrum formation in Rugby. When Jeff Sutherland developed the Scrum process at Easel Corporation in 1993, he used their study as the basis for team formation and adopted their analogy as the name of the process as a whole.
Scrum is a simple framework used to organize teams and get work done more productively with higher quality. It allows teams to choose the amount of work to be done and decide how best to do it, thereby providing a more enjoyable and productive working environment. Scrum focuses on prioritizing work based on business value, improving the usefulness of what is delivered, and increasing revenue, particularly early revenue. Designed to adapt to changing requirements during the development process at short, regular intervals, Scrum allows teams to prioritize customer requirements and adapt the work product in real time to customer needs. By doing this, Scrum provides what the customer wants at the time of delivery (improving customer satisfaction) while eliminating waste (work that is not highly valued by the customer).