The field of historical metrology studies past practices for measuring objects (or processes) as well as the transformations of such practices. This perspective leads to research questions that are distinctively different from those raised by the metrology for today’s natural sciences and engineering disciplines. In this paper we explain in what way published ontologies for scientific metrology fail to capture metrological practices and their transformations. We propose an ontology design pattern for modeling the practices described in historical metrological sources. We discuss the pattern’s conceptual components and link them to use cases from research in history.