Keh is the red storm and the last of the four colour-marked months, and the word is also the Mayan for deer, the same root that gives the K'iche' day name Kej. Whether the month name is the colour term or the animal is not settled between the sources, and both readings circulate in the literature.
Red is the colour of the east in the Maya scheme, the place of sunrise, and the deer is among the most frequently depicted animals in Maya art. The two readings are not in competition for the same evidence so much as drawn from different parts of it, and the atlas records the ambiguity rather than choosing.
A Maya date does not name a month and a number in the way a European one does. It names a day in the 260-day Tzolk'in, by number and sign, and a position in the 365-day Haab, by day and month, and the two together form the Calendar Round, which repeats only after 18,980 days, a little under fifty-two years. Within the Haab the days of a month are numbered from zero to nineteen, and the zero day is not called first but seated, the seating of the month, a usage the Classic inscriptions write with its own glyph.
The colour readings across the nineteen months are strongest where they come in sets. Wo and Sip pair as the black and the red conjunction, and Chen, Yax, Sak and Keh run black, green, white and red together, so an isolated colour gloss such as this one is supported by its neighbours rather than standing alone. That is the ordinary way ambiguous month names are argued in the literature, from the pattern rather than from the single word.