Sek is the fifth of the nineteen periods of the Haab, the 365-day Maya solar calendar. Recorded here by its Yucatec name, Sek, 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, reckoned from the seating of the month onward, alongside the interlocking Tzolk'in day sign and number. The Haab tracks the solar year of 365 days but takes no account of the extra quarter-day, so over centuries it drifts against the true seasons, a feature the Maya were aware of and worked within. These are the features of the Maya solar calendar, meshed with the sacred count in the fifty-two-year Calendar Round.
Sek, also transcribed Tzec, is the fifth month of the Haab, following Sotz. Its name's meaning is not confidently established; unlike Pop or Sotz, no widely accepted Yucatec etymology has been settled among epigraphers, and proposals remain tentative. Diego de Landa's account of the Yucatec ritual year places a ceremony honouring beekeeping and the harvest of honey and wax in this general part of the calendar, activities of real economic importance in pre-Columbian Yucatan, where honey was both a food and a trade good and wax supplied the copal-adjacent materials used in ritual. As with the neighbouring months, the exact alignment of Landa's described ceremonies to a single named month should be treated with some caution, since his account groups related observances across the surrounding weeks rather than assigning each rite to one Haab period alone.