This article seeks to contribute to the development of a method for analyzing the attributes of the gods of central Mexico in the manuscripts and the statuary from the time of the Spanish conquest. I focus on the Goddess of Water, Chalchiuhtlicue, “Jade Her Skirt.” The method consists of isolating the component designs of her array and grouping them in semantic groups. I begin by examining these designs and show that all of them were used in the notation of toponyms. These findings call into question the traditional separation between glyphs and icons. I next study the semantic groups and show that they consist of a series of culturally selected manifestations of water. Hence, it follows that the rules of composition of the goddess were grounded on a process of “definition by extension.” Thus, most of the semantic groups referred to different secondary names of the goddess, allowing us to think that they represented theonyms of a particular type.