The word "之上" is formed by combining the classical Chinese particle "之", which here functions as a grammatical linker indicating relationship or attribution, with the basic character "上", meaning "above" or "on". This fusion creates a single conceptual unit where "之" essentially points back to a previously stated object or place, and "上" then positions something in relation to it, resulting in the composite meaning of "on top of" or "above that". It is a fixed, inherited structure from literary Chinese that has been lexicalized into modern usage as a relational location term.