The concept of resilience has been used among a diversity of fields with a myriad of definitions. A systems approach to discovering the essence of resilience could aid in understanding its concept and provide opportunities to distinguish its systemic characteristics that can be identified, planned, or analyzed regardless of the field in which it is considered. In order to begin executing such an approach, a comprehensive study of the literature on the topic and circumstances in which resilience has been used or referred to in several fields of studies is necessary. In this paper, the conceptual common denominator of resilience is identified based on the results of a literature survey and according to the way it has been used in different contexts. This basis leads to the objective of this effort, and that is to recognize the systemic characteristics of resilience and demonstrate the defining of a universally accepted definition. Using a soft systems methodology and a supporting systemic diagramming technique entitled Systemigrams, we present the formulation of defining resilience in maritime homeland security. In this effort, many stakeholders contributed their thoughts and concerns on the meaning and operational use of resilience through a repetitive process to formulate a definition of the term. The result of this methodic approach is a general definition of resilience that has been refined in a collaborative environment via the application the Boardman Soft Systems Methodology.