Spirituality is a universal human phenomenon, yet conceptual confusion, ambiguity and scientific scepticism have prevented adequate investigation into its potential healing effects. A recent resurgence of interest in non-medical sources of healing and holistic medical practices is causing increased speculation regarding the nature of spirituality. The lack of conceptual clarity, and absence of a precise theoretical definition, prevent recognition of spiritual distress and, hence, appropriate nursing intervention. In this paper, current usage and definitions of spirituality are discussed and a philosophical definition of 'spirituality as integrative energy' is proposed. The metaphysical nature of this phenomenon makes it the proper concern of philosophy; consequently, a philosophical analysis of the aforestated proposition was completed using the five predicables of logic theory: species, genus, differentia, logical property and logical accident. Implications of this definition for providing holistic nursing care are also presented.