the act of choosing something or setting it apart (see Molina)
IPAspelling:
tɬɑseseknikiːʃtiːlistɬi
Alonso de Molina:
tlacececniquixtiliztli. apartamiento o escogimiento tal. Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 116r. col. 2. Thanks to Joe Campbell for providing the transcription.