The magic word hocus-pocus first appeared in Slavic languages as well as in Hungarian as an international loanword. Its original source has not been satisfactorily identified in the international etymological literature, and thus etymological dictionaries of the individual Slavic languages are not in agreement with respect to its provenance, either. The present paper assesses the possible explanations proposed in the literature, including that on Slavic and Hungarian etymologies, and makes an attempt at clarifying the origin and early history of this internationalism. In particular, it is claimed that the magic word hocus-pocus has probably been first coined in English. It may subsequently have been borrowed both by Slavic languages and by Hungarian via German. On the other hand, the English word is claimed to be ultimately of Latin origin, its most probable source being a fragment of the Latin text of the Roman Catholic holy mass; more specifically, part of the formula of transubstantiation: hoc est corpus meum ‘this is my body’.