Flow -> Right now this term is used to refer to the transfer of material or objects from an activity (as an output) to another activity (as an input), thereby connecting these two activities. In my opinion, changing this term to exchange does not affect the overall understanding of the ontology. Either would work. I can have a material flow from one activity to another activity.
Flow-object -> This is defined as an object that is referenced in a flow. Many flows can reference a single instance of a flow-object. I think this is where confusion may set in, as a flow-object can be imagined as an instance of flow. And I agree with Chris that this doesn’t sound right when talking about it. It just doesn’t seem natural to mention a flow object.
I don’t think flow itself works here as the word flow doesn’t equate to any object or material.
My initial idea to fix this is by making flow an adjective, as in the case of Flowing-Object. However, this doesn’t sound right in language as well. My previous argument for the flow-item would then be reversed; coal steel and those solid objects do not necessarily flow.
My secondary idea involves using the term Exchanged-Object. This is not necessarily related to the first term flow, but both can be adapted so that it sounds more congruent overall. This also sounds better as the question that arises from it sounds better in English (e.g. What’s the exchanged-object between the two activities you mentioned? In this flow, what’s the exchanged-object?)