This report focuses on one of the fundamental categories of music from the Volga-Ural region, Central Asia, and Western Asia, defined as kuy. This category is understood in its entirety, encompassing its dictionary and terminological meanings, as well as its various phenomenal reigns across the vast expanse of Eurasia. The report analyzes the numerous regional traditional forms of this phenomenon, its stylistic and structural features, and the specifics of its contemporary existence in a number of national musical cultures. A conclusion is reached regarding the category of kuy as a diversified system of worldviews that has become widespread within the Eurasian community. This community reveals both a diversity of musical manifestations and a common core uniting them through a number of representative features. The report is based on valuable audio and video materials, primary medieval sources, and relevant contemporary research in European and Eastern languages.