How to reach an agreement: not to generalize, but to specify.
If one person mentioned the President of the United States, and another mentioned Donald Trump, did they mean the same person? And if other people mentioned the President of the United States and George Washington, did they mean the same person as the person who mentioned the President of the United States in the previous sentence?
In engineering, a rigorous logic is needed for such reasoning of whether different descriptions refer to the same object. Is the pump P-101 described by one person on the piping diagram and the pump model PDR-15-NSH-12 described by another person in the assembly specification the same pump? And how does the pump PDR-15-NSH-12 installed in the turbine hall with serial number RKS456/4 relate to the first two descriptions? How to describe this "in the computer" so as not to confuse oneself and others?
Descartes (1596-1650) also pondered the question: how can one understand if people are talking about the same object when they see it with very different properties (i.e., associating it with very different classes)? For example, one engineer talks about a high-performance system, another about an explosive one, a manager about a profitable one, and a financial specialist about a cheap one? How can one understand here that they are talking about the same system? Descartes' answer to such questions is still used today: if the places in physical space-time/extents of two objects coincide (the shapes of the objects and their locations in space-time are the same), then it is the same object. It does not matter what primary or secondary characteristics, properties, and parts different people see in the object/system, or for what purposes they need that object/system. It does not matter if different people use the same or different names for those places in space-time they refer to in different situations. If they are talking about the same place in space-time, then they are talking about the same embodiment of the system. If I talk about food, you talk about an apple, she talks about a product, he talks about a green physical body weighing 150 grams, and all of us point to the same place/volume/form/extent in space-time/physical world, then we are talking about the same object. If someone points in the physical world/space-time to a butterfly with wings and says "butterfly," while someone else points to a changing over time and moving in space object egg-caterpillar-chrysalis-butterfly-with-wings and says "butterfly," then these two have a chance to understand each other, even if initially they could not agree due to confusion in words/terms.
It is important that here the "way to understanding" focuses on specifics (embodiment of the system, physical world) and not on "definition" (i.e., categorizing objects by their type— "definition by Aristotle," "as in dictionaries," as in mathematics textbooks). Issuing definitions, as well as demanding definitions, usually obscure understanding in complex situations. Understanding is clarified only by examples of embodiments of some systems in the physical world, "groundings" — such examples stop all disputes over terms.
If a glossary is included in a systems thinking course, and it contains a set of definitions, the understanding of the material will deteriorate: the formality of presentation will rise, and the connection with the physical world will worsen. In the final section of our course, titled "Instead of a glossary: ontology of the third-generation systems approach," we proposed a different way to address the issue of compactly describing a set of related concepts in the systems approach. If you really want to have a glossary, try reading this section instead of the glossary, and note: it unfolds into quite a large text if you refer to the literature mentioned there (tens of quite extensive primary texts).
If we do not require all reasoning, all descriptions of systems people make to ultimately be tied to the embodiments of systems, then we would not be able to verify if people are talking about the same thing or not. Moreover, there would be huge problems with verifying whether people are talking about the real world or expressing good wishes, or just fantasizing, or even consciously not wanting to bring their thoughts to reality. Emphasizing that the description and documentation of a system occur regarding the embodiment of the system in the physical world (rather than about something abstract allowing fantasies) allows to some extent to ignore the differences in terminology used by people. Ultimately, one can always verify whether people denote the same concept by different terms or different ones: even if abstract concepts are discussed, examples from the real world can always be provided to make these abstract concepts more concrete.
This does not mean abandoning descriptions: descriptions are needed to transfer knowledge about individual places in the physical world (embodiments of the system) to multiple such places (classes of systems). System descriptions support abstract thinking, but ultimately, everything is decided by the activity of changing the world, that is, the activity of embodiment/manufacturing/realizing the system in the real/physical world. Descriptions help keep focus on important considerations regarding the physical world, but not beyond that. The physical world is primary, system thinking keeps the focus on it, and for this purpose, the concept of system embodiment is used in system thinking.