 This study provides an overview of health and medical app definitions from an interdisciplinary perspective, using legal frameworks in the US, EU and Germany as a basis. The Narrative Literature Review identified 200 and 4 peer-reviewed publications that offered definitions of health and medical apps, with 11.8% included in the qualitative analysis. The study suggests that health apps are software programs on mobile devices that process health-related data for their users, including medical apps. Medical apps share the same technological functions and devices, and are intended for clinical and medical purposes, while health professionals, patients and family caregivers are the main user groups. This article was authored by Laura Moss, Meryl Frey, Chinchia Pan and others.