Cosmological knowledge is one of the most ancient and all-encompassing areas. In the historical evolution of philosophy, and later in the evolution of science in the modern understanding, concepts in this field were changing and various terms were being introduced and then disappeared. Therefore, a study of ancient works dedicated to cosmology is associated with certain difficulties. Modern astrophysical discoveries in the 21st century have imposed a need to introduce numerous new concepts into cosmological knowledge, their meaning not being clear enough so far. This state of affairs has brought about the need of a philosophical-hermeneutic scrutiny. The source-based examination principle must be recognized as a methodological condition of the study, as it enabled to identify the work of philosophers and natural scientists who most clearly expressed the ideas of cosmological knowledge. This approach made it possible to monitor the formation and evolution of cosmological terms in the history of science. In exploring modern literature, we used methods adopted in the hermeneutic-interpretative tradition; the greatest attention was paid to the methods of dialectical and comparative-historical analysis. The study has reached the following conclusions. The causes of terminological ambiguity in cosmology are: first, a different understanding of terms in different fields of knowledge; secondly, a change in the ideas about the object in history; thirdly, a need to introduce metaphors to describe incomprehensible phenomena.