The article which is written within the framework of linguopoetics analyses the sense-making mechanism from a cognitive perspective. The basic tool used to create this mechanism in O. Mandelstam’s poem "Palace Square" is vertical context. The vertical context of the poem under study is a complex structure consisting of not only separate linguistic units (historisms, archaisms, proper nouns, lexemes characteristic of religious discourse, quotations, and allusions) which have national and cultural specific features and require a commentary, but also a number of linguistic paradigms based on various principles of grouping. These principles are: taxonomic (passive vocabulary, including obsolete lexemes and religious discourse words), thematic (the lexico-semantic fields "The Roman Empire", "The Russian Empire", "Pushkinian Petersburg" and the semantic field "Faith"), figurative (metaphtonymies, aposiopesis, metaphors, metonymies, similes) as well as the relations between the elements of these paradigms. The units representing metaphtonymies which facilitate the formation of a "bunch of meanings" according to Mandelstam and the markers of aposiopesis (a trope requiring a deep ethnocultural analysis, which implies a "visualization" of the depicted urban landscape) pose the greatest difficulty in the process of analysis. The principles of repetition, antithesis, assimilation constitute the basis of the language composition of the poem. These principles interact with one another structuring the vertical context with respect to the artistic merit and making its semantic perspective broader.