Unifying nomenclature describing the individuals with Fontan circulation

Language shapes clinical care, research interpretation, and patient identity, particularly in chronic and heterogeneous conditions. Individuals living with a Fontan circulation represent a growing and diverse population unified by a surgically created physiology rather than a single anatomical diagnosis. Despite this, terminology used in clinical practice and research remains inconsistent, variably defining individuals by surgical procedure, anatomy, or loosely applied disease labels. Such variability complicates communication, limits comparability across studies, and risks reducing person-centered care. In this review, we examine the historical evolution and current use of terminology describing individuals with a Fontan circulation, highlight the clinical and research implications of inconsistent language, and delineate distinctions between anatomical substrates and shared Fontan physiology. We propose adoption of standardized, person-first nomenclature, specifically "individuals (or patients) with a Fontan circulation" with precise anatomical descriptors used where relevant. Unified terminology may enhance clarity, data harmonization, and patient-centered outcomes across the Fontan community.