The definition and characteristics of system have eluded humans for a very long time, as different people refer to the concept of system in various ways. A set of surveys conducted by us revealed seven distinct worldviews on system. We describe the surveys, analyze their results, and comment on differences between the responses. Based on the outcomes, we offer a comprehensive definition of system that can be accepted by the various worldview holders as an arrangement of parts or elements that together exhibit behavior or meaning that the individual constituents do not. Further, we present a compiled list of systemness characteristics—features that different worldview holders expect any system to exhibit. Then we present and describe the different worldviews on system, compare them with previous system definitions, and map them to five system domains. We conclude that the various system worldviews offer useful perspectives for systems engineers, who should have the flexibility to accept the fact that different worldviews may be appropriate for different situations and be ready to adopt them as necessary.