Scope Change

In almost any successful project management endeavor it is conceivable that some change in scope might be necessary. Veering from the initial scope of the project could potentially cause costs to mount or deadlines to be unmet.
Managing these scope changes can be challenging for even the most skillful project manager. First, the baseline for change must be identified then proper management of the change in scope is required.
Once potential changes have been identified they should to be analyzed and prioritized so that managers can take steps necessary to address and make effective decisions about each one. Sometimes these changes can seem overwhelming and endless so it is important that the project management team have an understanding of the dynamics of change to prevent possible project failure.
To deal with project modifications the manager must determine which changes will be made and how each one might impact the project deliverables as well as how variation from the perceived scope might influence the final outcome of the project.
Some scope change is inevitable however it is important to weigh each proposed change and evaluate its potential impact on overall project management.

This term is defined in the 3rd and the 4th edition of the PMBOK.