Project management is an integrative endeavor - an action, failure to take an action will usually affect other areas. Hence the concept of project management as a number of interlinked processes.
A process is a series of actions bringing about a result.
Project processes are performed by people and generally fall into one or two main categories.
Project management processes are concerned with describing and organizing the work of the project.
Product-oriented processes are concerned with specifying and creating the project product. They are typically defined by the project life cycle.