to use one's palm as a form of signaling (see Molina)
Orthographic Variants:
macpalmachiotia
Alonso de Molina:
macpalmachiotia. nitla. (pret. onitlamacpalmachioti.) señalar algo con la palma de la mano. 71m2-51r. col. 1. Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. Thanks to Joe Campbell for providing the transcription.