Discipline-specific terminology is a central element of the vocabulary used by dentists and scientists in the context of their professional activities and plays a critical role in the understanding of dentistry. A number of controversial terms and non-standardized definitions exist in the field of endodontology. For example, in root and canal anatomy, variations exist in the definitions of root morphology (including apical bifurcation, fusion and dilaceration), pulp chamber anatomy (including the outline of the floor, pulp horns and location of the root canal orifice), apical root canal bifurcations, canal isthmuses, accessory canals and apical foramen. This narrative review provides a critical analysis of a range of controversial terms currently used to describe root and canal anatomy. It also addresses the consequences of using such controversial terms on the accuracy and reliability of research findings and clinical practice.