Life cycle model
A software life cycle model (also called process model) is a descriptive and diagrammatic representation of the software life cycle.
A life cycle model represents all the activities required to make a software product transit through its life cycle phases. It also captures the order in which these activities are to be undertaken.
In other words, a life cycle model maps the different activities performed on a software product from its inception to retirement.
Different life cycle models may map the basic development activities to phases in different ways. Thus, no matter which life cycle model is followed, the basic activities are included in all life cycle models though the activities may be carried out in different orders in different life cycle models. During any life cycle phase, more than one activity may also be carried out. For example, the design phase might consist of the structured analysis activity followed by the structured design activity.
Basics of Software Life Cycle | software engineering