Yucatec Akbal, K'iche' Aq'ab'al, is the day of night and of the darkness before first light. The two names are transparently the same word in two Mayan languages, both built on the root for night, and the Classic glyph for the day is one of the more readily recognised of the twenty in the inscriptions.
The central Mexican parallel is instructive because it does not match. Third position in the tonalpohualli is Calli, house, not night, and this is one of the handful of places where the shared twenty-sign sequence carries different imagery on either side of the Isthmus. The usual explanation is that both signs draw on the same idea of enclosure and interior darkness, the house being the dark place, but the divergence is real and should not be smoothed away; the count travelled and was translated, and translation leaves marks.
In use, Aq'ab'al is understood by living daykeepers as a day of dawn and of things beginning to be visible, which is a reading of the same darkness from the other end rather than a contradiction of it, since the night is named from the light that ends it. Akbal opens a trecena once in each 260-day round, giving its character to the twelve numbered days that follow, and it is not one of the four Year Bearers in either the Classic set of Ik, Manik, Eb and Kaban or the Postclassic Yucatec set of Kan, Muluc, Ix and Kawak that Diego de Landa recorded.