Aims and objectives: To generate a standardised definition for fundamental care and identify the discrete elements that constitute such care. Background: There is poor conceptual clarity surrounding fundamental care. The Fundamentals of Care Framework aims to overcome this problem by outlining three core dimensions underpinning such care. Implementing the Framework requires a standardised definition for fundamental care that reflects the Framework's conceptual understanding, as well as agreement on the elements that comprise such care (i.e., patient needs, such as nutrition, and nurse actions, such as empathy). This study sought to achieve this consensus. Design: Modified Delphi study. Methods: Three phases: (i) engaging stakeholders via an interactive workshop; (ii) using workshop findings to develop a preliminary definition for, and identify the discrete elements that constitute, fundamental care; and (iii) gaining consensus on the definition and elements via a two-round Delphi approach (Round 1 n = 38; Round 2 n = 28). Results: Delphi participants perceived both the definition and elements generated from the workshop as comprehensive, but beyond the scope of fundamental care. Participants questioned whether the definition should focus on patient needs and nurse actions, or more broadly on how fundamental care should be delivered (e.g., through a trusting nurse–patient relationship), and the outcomes of this care delivery. There were also mixed opinions whether the definition should be nursing specific. Conclusions: This study has initiated crucial dialogue around how fundamental care is conceptualised and defined. Future work should focus on further refinements of the definition and elements with a larger, international group of practising nurses and service users. Relevance to clinical practice: The definition and elements, through ongoing refinement, will contribute to a robust evidence base that will underpin policy development and the systematic and effective teaching, delivery, measurement and evaluation of fundamental care.