Life purpose is an important thread of critical care nursing. However, no consensus exists for a definition of life purpose. In addition, ambiguity prevails regarding the manner in which life purpose is incorporated into nursing practice and research. Therefore, through a conceptual synthesis process, this article aims to clarify the essence of life purpose with relevance to health and critical care nursing today. The outcome of the conceptual synthesis is an operational definition to be used in future nursing research. Information was obtained from a literature search of scholarly articles using (1) searches of electronic databases of literature about life purpose and (2) research studies addressing conceptual, substantive, and methodological domains. Topics consisted of the philosophical underpinnings of life purpose, its attributes, definitions, and theoretical frameworks, along with differences in theories and empirical support. Finally, emerging from this process, the article culminates with a proposed conceptual definition of life purpose, which may be applied broadly to older adults in various critical care settings.