This paper presents the ongoing refinement of a construct (a Rational Mathematical Template, RMT) emerging from observations of effective classroom discussions that are aimed at producing a definition, statement of a theorem, proof for a given statement, mathematical model for a physical situation, etc., as key elements of mathematical rationality. An RMT concerning one of these elements provides students with guidelines for how to manage the related process of production in a conscious way and how to check the validity of the product. In order to introduce the RMT construct, the paper refers to two episodes of definition production. A brief discussion of the analogies and differences with other constructs follows. The paper ends with an outline of possible developments of the refinement of the RMT construct and related educational issues.