The term ‘mythologem’ enters depth psychology principally through the collaborative work of C. G. Jung and Karl Kerényi, where it designates not myth in the loose, popular sense but a specific, technically precise unit of mythological material: a traditional tale, already ancient and well-known, yet still plastic and amenable to reshaping. Kerényi’s foundational formulation — that mythologem names ‘tales already well known but not unamenable to further reshaping’ — insists on both fixity and mobility, establishing mythology as a fluid yet substantial body of material analogous to musical theme and variation. Jung adopts the term to anchor his archetypal hypothesis in concrete cultural data, treating mythologems as empirical expressions of collective psychic structures rather than allegorical inventions. Across the corpus, mythologems function at several registers: as ethnological evidence spanning Hainuwele, Finnish, Altaic, and Eleusinian traditions; as depth-psychological testimony to the reality of archetypes such as the Divine Child, Kore, and the trickster; and as hermeneutic instruments permitting honest, non-dogmatic discussion of theological imagery. Kerényi’s solo work extends the concept into analyses of Hermes and Eros, reading mythologems as ontological revelations of divine being rather than cultural artifacts. The central tension in the corpus is whether mythologems are best understood as historical-ethnological data or as spontaneous psychic productions — a tension the Jung-Kerényi collaboration never fully resolves but productively sustains.