The article deals with some linguistic aspects of the functioning of Greek mythological proper names (gods, heroes etc.), which became precedent nouns-mythonyms in the Modern Greek language, expanding their semantic structure. Over the course of millennia, mythonyms underwent a number of semantic changes and expanded their meanings; in this regard, the relevance of our research is due to the fact that analysis of precedent mythonyms serves as the key to a clearer understanding of the national linguistic picture of the world of a native Greek speaker and of the meaning and influence of ancient Greek mythology in Modern Greek. The purpose of the study is to identify the additional meanings formed during the actualization of mythonyms as precedent proper names in the discursive field of Modern Greek culture. Semantic derivation is the way of mythonyms’ integration into the discourse of the Modern Greek language, and proper names become common nouns because of their precedental character. The results show that the most frequent parameters for the transformation of mythonyms into precedent names are behavior, character and appearance of the hero or goddess, and these main features create metaphoric transfer and create the precedental character. The analysis expands the understanding of how semantic transformation forms the field of mythonyms’ precedentality in Modern Greek; thus, we take the first step to create a dictionary of precedentality based on the Greek language.