Theory building is complex and ongoing. Theories need to be constantly tested and the underlying constructs explored. This study, which is in support of Dr. Michael G. Moore’s theory of transactional distance, is exploratory and descriptive, and focuses on one of the key variables in the theory: dialogue. As discussed by Dr. Moore and Dr. Nicholas C. Burbules, dialogue is a purposeful journey that an individual or group undertakes with others to expand understanding and create new knowledge. Dialogue is not depicted by any one singular event, but the destination hopefully results in "aha" moments when concepts and constructs around ideas become clear. Through a review of the literature on dialogue in education, this study proposes a conceptual definition of dialogue for online learning environments based on the works of Burbules and Moore, and a classification scheme for dialogue based on the philosophical work of Burbules on dialogue. The study only represents a starting point and provides baseline tools so future studies can explore the affect of dialogue on transactional distance and the other key variables of the theory: structure and autonomy.