the crown of the head, or the middle of the head (see Molina)
Orthographic Variants:
quayollotli
Alonso de Molina:
quayollotli. la coronilla, o el medio dela cabeza. Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 84r. col. 2. Thanks to Joe Campbell for providing the transcription.