a mediator; or, something that falls in the middle of something (see Molina)
Orthographic Variants:
nepantla ycac
Alonso de Molina:
nepantla ycac. medianero, o cosa que esta en medio de algo. Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 69r. col. 1. Thanks to Joe Campbell for providing the transcription.