In simple terms, Scrum is an Agile methodology to project management. In the literature on Agile project management and development, Scrum methodology is often called “Scrum approach” or “Scrum method“. Personally I prefer using the term “Scrum methodology” – meanwhile any of the terms is correct and can be equally used to describe Scrum requirements and the basic concept.
If being more precise, Scrum methodology for project management refers to a team-based collaborative approach to iterative and incremental development of projects (often IT projects) to create a product during small cycles called iterations and to increase functionality of the product during each iteration by adding new properties. The method lets build a project team that includes such roles as Product Owner, Scrum Master and Scrum Team. Each of the roles has different Scrum tasks and operations to perform.