Aims Remote clinical decision-making (RCDM), commonly known as 'telephone triage' or 'hear and treat', describes clinicians' non-face-to-face involvement with patient care, and is an established strategy in UK ambulance services for managing increasing demand. However, there is no suitable definition of RCDM that fully explains the roles undertaken by clinicians in 999 hubs, or for its use as an ambulance quality indicator (AQI). The aim of this study, which is part of a larger evaluation of a new RCDM module in higher education, is to determine how clinicians define RCDM. Methods Three participants were asked, during semi-structured interviews, to define RCDM. The interviews were recorded, transcribed and thematically analysed. Results Clinicians do not focus on outcomes when defining RCDM, but on the efficacy of the process and the appropriateness of the determined outcome. Conclusion There is no precise description of the role of healthcare professionals in 999 clinical hubs, but there is a need for role clarity, for employees and organisations. The study questions the suitability of the definition of hear and treat as an AQI, as it does not appear to represent fully the various duties undertaken by 999 clinical hub healthcare professionals. More research is needed to consider the definition of RCDM in all its forms.