We introduce and formalize the key elements of a recent approach [25] to function definition that covers both biological and artefact functions. The paper concentrates on the steps from informal definitions to formal expressions and aims to show how to develop an ontological module for generic function representation. This part is done assuming the YAMATO ontology as background system. The second goal of the paper discusses how the module could be adapted to other foundational ontologies. In this part, we first point out the ontological assumptions on which the module relies and then discuss problems in reformulating them in other systems. This step is needed to verify whether and how the function module can be meaningfully used in other ontologies. We exemplify this case by discussing BFO and DOLCE, and by formalizing the module in the latter ontology.
