Kevin M. Roessger is an assistant professor of adult and lifelong learning at the University of Arkansas. He teaches courses in all areas of adult learning and development. His research interests include behavioural analytic approaches to skills-based learning and reflection as a natural phenomenon. Current conceptualisations of reflection have limited value for adult educators and researchers interested in predicting and influencing learning on measurable outcomes. They fail to specify how prediction and influence might occur and what might be expected to result. Ambiguous definitions prevent systematic investigations of reflection's effects and replication and extension of researchers' work. To address these issues, a functional account of Dewey's meaning making criterion of reflection is presented using relational frame theory. It aims to (a) specify how reflection occurs from functional relationships with the environment, (b) minimise conjecture by extending generalisable research findings, (c) address causality in reflective learning, (d) align with egalitarian ideals by conceptualising reflection as a learned skill and (e) provide a basis for a research programme using precise terminology and technical definitions. A functional definition is offered along with an outcome for reflection: transforming existing meaning of events related to the conceptualised self.