a wooden support for a door, one that penetrates the wall (see Molina; transl. to English here by SW)
Orthographic Variants:
tlatzacuillo elquauhyotl
Alonso de Molina:
tlatzacuillo elquauhyotl. tranca de puerta. s. el madero que entra enla pared. &c. Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 142v. col. 1. Thanks to Joe Campbell for providing the transcription.