Scrum is the most used framework for Agile product delivery. Often, people wonder about the name, its origins, and what it means. Let's have a look at the origins of the term 'Scrum.' And, as a result, understand that it is not an acronym.
The term 'Scrum' was first used by Hirotaka Takeuchi and Ikujiro Nonaka in their ground-breaking 1986 paper, "The New New Product Development Game." They borrowed the name from the game of rugby to stress the importance of working as a team in complex product development. This was about complex product development in general, not only software products. Their research showed that outstanding performance is achieved when teams are small and self-organizing units of people and when such teams are fed with (challenging) objectives, not with executable tasks. Teams can only achieve greatness when given room to devise their own tactics to best head towards shared objectives.
The well-known Agile development method inherited its name 'Scrum' from this paper as it thrives on the same principles for developing and sustaining complex software products. Those principles are time-boxing of work, creating releasable ("Done") products, and self-organization of teams that - collectively - have all the skills required to create products in a releasable state, where releasable means "ready to ship to the market."
The Japanese authors of the paper consider the concept that they named 'Scrum' as the necessary core of any system that pretends to be Lean. But, they never use the term 'Lean' as such, because it has become synonymous to an outside interpretation and copy of the perceived management practices of the Toyota Production System.
These management practices are not the core of Takeuchi and Nonaka's development system. That core was named 'Scrum' by the authors. Lean management practices should simply be complementary to it. There can't be 'Lean' if the heart of it, Scrum (as named by the authors), is overlooked, which, in general, is the case. The authors, therefore, prefer to stress the need for the heart and soul of the system to be Scrum and take away the sole focus on the surrounding management practices. They never talk of Lean, but always speak about Scrum.
As Scrum is no acronym, there is no reason to write "SCRUM."