Kayab is the seventeenth of the nineteen periods of the Haab, the 365-day Maya solar calendar. Recorded here by its Yucatec name, Kayab, associated with the turtle and, in some readings, with song, the month is known from the colonial sources and, in its glyphic form, from the Classic inscriptions. Like each of the eighteen full months it counts twenty days, and a Maya date names a day by its position within the month alongside the interlocking Tzolk'in day sign and number. These are the features of the Maya solar calendar, built of eighteen twenty-day months and a closing five-day period. With the following month, Kumku, it brings the eighteen full months toward their close before the short final period of the year.
Kayab, the seventeenth month, is generally translated with reference to the turtle, a reading epigraphers connect to Classic-period imagery in which a turtle carapace can represent the surface of the earth, most famously in depictions of the maize god emerging from a cracked turtle shell, an image widely read as the mythic sprouting of maize from the earth's surface after the agricultural rains. Whether Kayab's own glyph specifically encodes this turtle-earth symbolism, or the month name's connection to turtles rests on a separate and more limited linguistic association, is not settled with full certainty among specialists, and this atlas notes the plausible but not conclusively proven link rather than presenting it as an established fact.