'Chalcedonian' originates from Greek, specifically the place name 'Chalkēdōn' (Χαλκηδών), where the element 'chalkos' meant 'copper' (the name referred to the ancient town of Chalcedon); the English adjectival/ethnic suffix '-ian' (via Latin/Medieval Latin) denotes 'belonging to' or 'pertaining to'.

'Chalcedonian' changed from Medieval Latin 'Chalcedonius' (used to denote someone or something from Chalcedon or associated with the council held there) and eventually became the modern English word 'Chalcedonian' via church- and theological-latin usage.

Initially it meant 'of or from Chalcedon' (a geographical/ethnic sense), but over time it evolved into its primary modern meaning of 'a supporter or adherent of the Council of Chalcedon's doctrinal definition' in theological contexts.