CMMI is defined in terms of Process Area (PA), which are group of tasks to be performed to accomplish particular activity. For example Project Planning (PP) process area defines all tasks to be performed to plan the project. There are total 22 PAs. There is another dimension defined in this model known as Level (Capability or Maturity), which applies to all PAs similarly. The level focuses on what need to be accomplished in PA and Level 2 to 5 focus on how good PA can be performed. These concepts are explained during CMMI trainings. Please refer Training page for details.