In terms of the project management related terminology, the term integrated refers specifically to any particular component, element, or activity that takes place as part of the project that is considered to be completely and utterly tied in, interlocked, interconnected, or meshed with another element, component, or activity that takes place within the overall project process. These interconnected, interlocked, and interrelated components can then when all is said and done be blended and ultimately unified to form a cohesive and functioning and completely unified whole. The effective and proper integration of all of these components is absolutely essential to the seamless flow of the activity throughout all of the varied processes that must take place within the overall activity. The determination of which particular components within the activity should be part of an overall integration process can be determined at any time in the life cycle of the project and is usually a group decision made by the project management team along with the team leader
This term is defined in the 3rd edition of the PMBOK but not in the 4th.