Scrum is a management framework for incremental product
development using one or more cross-functional, self-organizing teams
of about seven people each.
It provides a structure of roles, meetings, rules, and artifacts. Teams are
responsible for creating and adapting their processes within this
framework.
Scrum uses fixed-length iterations, called Sprints, which are typically
two weeks or 30 days long. Scrum teams attempt to build a potentially
shippable (properly tested) product increment every iteration.