a woman's custom (menstruation); or, a woman's blouse (see Molina)
Orthographic Variants:
nemetzuiliztli
Alonso de Molina:
nemetzuiliztli. costumbre, o camisa dela muger. Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 67r. col. 2. Thanks to Joe Campbell for providing the transcription.