Scope (project management)
In project management, the term scope has two distinct uses- Project Scope and Product Scope.
Scope involves getting information required to start a project, and the features the product would have that would meet its stakeholders requirements.
- Project Scope
- "The work that needs to be accomplished to deliver a product, service, or result with the specified features and functions."
- Product Scope
- "The features and functions that characterize a product, service, or result."
Notice that Project Scope is more work-oriented, (the hows,) while Product Scope is more oriented toward functional requirements. (the whats.)
Scope creep 
Scope creep management is important for effective project management. Projects are expected to meet strict deadlines with resource restraints, and an unvetted and unapproved change in the scope can affect the success of the project. Scope creep sometimes causes cost overrun.
Scope creep is a term which refers to the incremental expansion of the scope of a project, which may include and introduce more requirements that may not have been a part of the initial planning of the project, while nevertheless failing to adjust schedule and budget. There are two distinct ways to separate scope creep management. The first is business scope creep, and the second is called features (also technology) scope creep. The type of scope creep management is always dependent on the people who create the changes.
Business scope creep management occurs when decisions that are made with reference to a project are designed to solve or meet the requirements and needs of the business. Business scope creep changes may be a result of poor requirements definition early in development, or the failure to include the users of the project until the later stage of the systems development life cycle. Management system. Items deemed out of scope go directly through the change control process and are not automatically added to the project work items. The Project Scope Management plan is included in as one of the sections in the overall Project Management plan. It can be very detailed and formal or loosely framed and informal depending on the communication needs of the project.
Features (Technology) scope creep occurs when the scope creep is introduced by technologists adding features not originally contemplated. Customer-pleasing scope creep occurs when the desire to please the customer through additional product features adds more work to the current project rather than to a new project proposal. Gold-plating scope creep occurs when technologists augment the original requirements because of a bias toward "technical perfectionism" or because the initial requirements were insufficiently clear or detailed.
See also 
- A Guide to the Project Management Body of Knowledge (PMBOK Guide) - Fourth Edition. Project Management Institute, 2008. ISBN 978-1-933890-51-7