Riddle is one of the oldest syncretic genres of folklore, which both regulated the key events in human life and translated the centuries-old life experience of the people. Despite the oral form of existence, many riddles have retained their original structure, as well as linguistic and cultural identity based on national archetypal thinking and national mythologies. The aim of the work is to study the cosmogonic riddles of the Russian and Tatar languages, to identify the specifics of their imaginative organization. The study establishes unique and universal characteristics for each object, allowing one to decode the information of color, temporal characteristics, and number of the object, its form and relationship with other objects. Particular attention is paid to the secondary nomination of the moon and the sun, having national specifics. In the Russian riddle, according to East Slavic tradition, the zoomorphic code (with lexemes “a cow”, “a bull”, “a horse”, “a stallion”) was widespread because it was indicative of the magic character of the described subject. In the Tatar national riddle there is an input of the lexemes designating the related relations (the father, mother, the sister, the brother) that in its turn reflects national mythology about the earth and the sky creation. In this article the authors examine the problem of the input of the secondary nomination of the denotation and its mythological causality. Linguistic material is accompanied by a linguistic and cultural commentary, which allows a deeper insight into the process of denotation coding. The method of content analysis and the method of linguistic reconstruction of culture were used in the work. The results of the research can be useful for folklorists, linguists dealing with the issues of national cultures, their reflection in the folklore text.