Spirituality is a complex concept that has different meanings for different people. Spiritual care is a fundamental aspect of nursing and attending to the spiritual needs of patients may improve their health outcomes. This article, the first in a series of three, explores various definitions of spirituality, and the importance of spirituality and spiritual care in healthcare settings. The second article of this series provides an in-depth exploration of the assessment of patients' spiritual care needs, and the third and final article in this short series discusses spiritual care nursing interventions.