In linguistics, onomastics is the science that studies the history and origin of toponyms, along with their structural aspects. This study aimed to determine the origin of toponyms by comparing their linguistic and ethnocultural, as well as mythical, information. A qualitative research design guided this study. A few toponyms were identified through random sampling method including Yrgyz (Irgiz), Burkanbulak, Esik (Yssyk), Auliesu, Zhaiyk (Ural) and Zher-Su, which were collected from etymological, explanatory and mythological dictionaries and collections of mythical texts. The etymological and component analysis methods were applied to study these names. The criteria to select these toponyms were that all should be names of rivers or hydronyms, since river-water was a mythological symbol (the source of life, death and disorder); and that they should occur not only in one language, but in several related languages. The findings revealed that the archetype of each word conformed to phonetic changes. There were also structural connections between these words. Besides, each word had symbolic connotations. This study would provide useful insights about ethnocultural and mythical information of these words and help in broader understanding of the cultural characteristics.