In the broad community, the term “system” may mean a collection of technical, natural or social elements, or a combination of all three. This may produce ambiguities at times: for example, does “management” refer to management of the SE process, or management of the system being engineered? As with many special disciplines, SE uses terms in ways that may be unfamiliar outside the discipline. For example, in systems science and therefore SE, “open” means that a system is able to interact with its environment--as opposed to being "closed” to its environment. However, in the broader engineering world we would read “open” to mean “non-proprietary” or “publicly agreed upon.” In such cases, the SEBoK tries to avoid misinterpretation by elaborating the alternatives e.g. “system management” or “systems engineering management”.

The SEBoK seeks to position SE within the broader scope of knowledge which considers systems as part of its foundations. To do this without attempting to re-define general systems terminology, SEBoK introduces two related definitions specific to SE:

• An engineered system is a technical or socio-technicalsystem which is the subject of an SE life cycle. It is a system designed or adapted to interact with an anticipated operational environment to achieve one or more intended purposes while complying with applicable constraints.
• An engineered system context centers around an engineered system but also includes in its relationships other engineered, social or natural systems in one or more defined environments.